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(S ffliPMIE PROJECTS 770262 361089
(1 Ingenuity Unlimited Network fV (SBpeonBG SoaiFg]©^ {7D®D®CoT fo)(oli WIND GENERATORS 380 WATT 1 14 metre dia blades transmitter kit 3 RF stages, mic & audio preamp inc £24 ref 1028 200 WATT INVERTERS plugs straight into your car carbon matrix blades 3 year warranty, 12vdc output, 24v version PIR CAMERAsuiit in CCTV camera (composite output) IR available, control electronics included, brushless neodymium cubic cigarette lighter socket and is fitted with a 13A socket so you can run curve alternator, only two moving parts, maintenance free, simple roof strobe light, PIR detector and battery backup Designed to squirt" your mams operated devices from your car battery £49 95 ref SS66 top installation, start up speed 7mph, max output (30mph) 380w £499 pictures down the 'phone line but works well as a standalone unit THE TRUTH MACHINE Tells if someone is lying by micro ref AIR1 Bargain price £49 95 ref SS81, 3 or more £44 95 ref SS80 tremors in their voice, battery operated works in general conversation HYDROPONICS DO YOU GROW YOUR OWN? We have a full 4AH D SIZE NICADS pack of 4£10 ref 4AHPK and on the 'phone and TV as well' £42 49 ref TD3 colour hydroponics catalogue available containing nutrients, ELECTRIC FENCE KIT Everything you need to build a 12vdc INFRA RED FILM 6" square piece of flexible infra red film that will pumps, fittings, enviromental control, light fittings, plants, test electnc fence complete with 200m of electric fence wire £49refAR2 omy allow IR light through Perfect for converting ordinary torches TELEKINETIC ENHANCER PLANS Mystify and amaze your lights, headlights etc to infra red output only using standard light bulbs friends by creating motion with no known apparent means or cause SENDER KIT Contains all components to build a A/V transmitter Easily cut to shape 6" square £15 ref IRF2 Uses no electrical or mechanical connections no special gimmicks yet complete with case £35 ref VSXX2 HYDROGEN FUEL CELL PLANS Loads of information on produces positive motion and effect Excellent for science projects, UV LIGHTS 4' flourescent 340nm £38.99 ref UV23 hydrogen storage and production Practical plans to build a Hydrogen magic shows, party demonstrations or serious research & development 33 KILO LIFT MAGNET Neodymum 32mm £15 ref MAG33 fuel cell (good workshop facilities required) £8 set ref FCP1 of this strange and amazing phychic phenomenon 10 WATT SOLAR PANEL Amorphous silicon panel fitted m a STIRLING ENGINE PLANS Interesting information pack £4/set Ref F/TKE1 anodized aluminium frame Panel measures 3" by 1' with screw covenng all aspects of Stirling engines, pictures of home made ELECTRONIC HYPNOSIS PLANS & DATA This data terminals for easy connection 3' x 1* solar panel £55 ref MAG45 engines made from an aerosol can running on a candle' £ 12 ref STIR2 showsseveralwaysto put subjects under your control Included is a full Unframed 4 pack (3'xr) £58.99 ref SOLX ENERGY SAVER PLUGS Saves up to 15% electricity when volume reference text and several construction plans that when 12V SOLAR POWERED WATER PUMP Perfect for many used with fridges motors up to 2A, light bulbs, soldenng irons etc £9 ea assembled can produce highly effective stimuli This material must be 12v DC uses ranging from solar fountains to hydroponics' Small and ref LOT71, 10 pack £69 ref LOT72 used cautiously It is for use as entertainment at parties etc only, by compact yet powerful Will work direct from our 10 watt solar panel in 12V OPERATED SMOKE BOMBS Type 3 is a 12v trigger and those expenenced in its use £15/set Ref F/EH2 bright sunlight Max head 17 ft Max flow = 8 Lpm,1 5ARefAC8 £18 99 3 smoke canmsters. each canmster will fill a room in a very short space GRAVITY GENERATOR PLANS This unique plan demonstrates SOLAR ENERGY BANK KIT 50x 6"x12" 6v solar of time' £14 99 ref SB3 Type 2 is 20 smaller canmsters (suitable for a simple electrical phenomena that produces an anti-gravity effect You simulated equipment fires etc) and 1 trigger module for £29 ref SB2 can actually build a small mock spaceship out of simple materials and panels(amorphous)+50 diodes £99 ref EF112 Type 1 is a 12v trigger and 20 large canmsters £49 ref SB1 without any visible means- cause it to levitate £10/set Ref F/GRA1 PINHOLE CAMERA MODULE WITH AUDIO! Superb HI POWER ZENON VARIABLE STROBES Useful 12v PCB WORLDS SMALLEST TESLA COIL/LIGHTENING board camera with on board sound' extra small just 28mm square fitted with hi power strobe tube and control electronics and speed DISPLAY GLOBE PLANS Produces up to 750,000 volts of (including microphone) ideal for covert surveillance Can be hidden control potentiometer Perfect for interesting projects etc 70x55mm discharge, experiment with extraordinary HV effects 'Plasma in a jaf, inside anything even a matchbox' Complete with 15 metre cable, psu 12vdc operation £6 ea ref FLS1, pack of 10 £49 ref FLS2 St Elmo's fire, Corona, excellent science project or conversation piece and tv/vcr connnectors £73 95 ref CC6 DRILL OPERATED PUMP Fits to any drill in seconds, uses £5/set Ref F/BTC1/LG5 SOLAR MOTORS Ti ny motors which run quite happily on voltages standard garden hose, pumps up to 40 gph' £8 99 ref DRL3 VOICE SCRAMBLER PLANS Mmature solid state system turns from3-12vdc Works on our 6v amorphous 6" panels and you can run speech sound into indecipherable noise that cannot be understood them from the sun' 32mm dia 20mm thick £1 50 each NEW LASER POINTERS 4 5mw, 75 metre range, hand held unit without a second matching unit Use on telephone to prevent third party WALKIE TALKIES 1 MILE RANGE £37/PAIR REF MAG30 runs on two AA batteries (supplied) 670nm £29 ref DEC49 listening and bugging £6/set Ref F/VS9 DRILL OPERATED PUMP Fits to any dnll in seconds uses HOW TO PRODUCE 35 BOTTLES OF WHISKY FROM PULSED TV JOKER PLANS Little hand held device utilises standard garden hose, pumps up to 40 gph' £8 99 ref DRL3 A SACK OF POTATOES Comprehensive 270 page book pulse techniques that will completely disrupt TV picture and sound' GIANT SCREEN VIEWERTum your TV picture into a supersize covers all aspects of spirit production from everyday materials works on FM too' DISCRETION ADVISED £8/set Ref F/TJ5 screen' This high precision Fresnel lens converts even the smallest Includes construction details of simple stills etc £12 ref MS3 BURNING. CUTTING C02 LASER PLANS Projects an screen up to a massive 26" at a fraction ot the cost of a big TV Easily NEW HIGH POWER MINI BUG With a range of up to 800 invisible beam of heat capable of burning and melting materials over a fitted in minutes Also ideal for PC monitors etc £26 95 ref SVGA2 metres and a 3 days use from a PP3 this is our top selling bug' less considerable distance This laser is one of the most efficient, converting TELEPHONES Just in this week is a huge delivery of telephones, than 1" square and a 10m voice pickup range £28 Ref LOT 102 10% input power into useful output Not only is this device a workhorse all brand new and boxed Two piece construction with the following BUILD YOU OWN WINDFARM FROM SCRAP New in welding, cutting and heat processing matenals but it is also a likely features- Illuminated keypad, tone or pulse (switchable) reacall publication gives step by step guide to building wind generators and candidate as an effective directed energy beam weapon against redial and pause, high/lew and off nnger switch and quaNty construction propellers Armed with this publication and a good local scrap yard missiles, aircraft, ground-to-ground, etc Particle beams may very well finished in a smart off white colour and is supplied with a standard could make you self sufficient in electncity' £12 ref LOT81 utilize a laser of this type to blast a channel in the atmosphere for a high international lead (same as US or modems) if you wish to have a BT CCTV CAMERA MODULES 46X70X29mm, 30 grams, 12v energy stream of neutrons or other particles The device is easily lead supplied to convert the phones these are also available at £1 55 100mA auto electronic shutter, 3 6mm F2 lens, CCIR, 512x492 applicable to burning and etching wood, cutting, plastics, textiles etc each ref BTLX Phones £4.99 each ref PH2 pixels, video output is 1v p-p (75 ohm) Works directly into a scart or £12/set Ref F/LC7 LIQUID CRYSTAL DISPLAYS Bargain prices, video input on a tv or video IR sensitive £49 ref EF137 ULTRASONIC BLASTER PLANS Laboratory source of sonic 20 character 2 line, 83x19mm £3.99 ref SMC2024A IR LAMP KIT Suitable for the above camera, enables the camera shock waves Blow holes in metal, produce "cokT steam atomize 16 character 4 line, 62x25mm £5.99 ref SMC1640A liquides Many cleaning uses for PC boards, jewllery, coins, small parts to be used in total darkness' £6 ref EF138 etc £6/set Ref F/ULB1 40 character 1 line 154x16mm £6 00 ref SMC4011A UK SCANNING DIRECTORY As supplied to Police, MOD M15 ANTI DOG FORCE FIELD PLANS Highly effective circuit LM255X HITACHI LAPTOP SCREENS 240x100mm. and GCHQ' coverers everything from secret government frequencies, produces time vanable pulses of accoustical energy that dogs cannot 640x200 dots. New with data £15 ref LM2 eye in the sky. prisons, military aviation etc £18 50 ref SCANB SEALED LEAD ACID BATTERIES INFRA RED POWERBEAM Handheld battery powered lamp, 4 tolerate £6/set Ref F/DOG2 inch reflector gives out powerful pure infrared light' oerfect for CCTV LASER BOUNCE LISTENER SYSTEM PLANS Allows you 12V 6.5AH. NEW £12 REF BATT12 use mghtsights etc £29 ref PB1 to hear sounds from a premises without gaming access £ 12/set Ref F/ 12V 6.5AH, S/HAND PACK OF 5 £20 REF EF99 SUPER WIDEBAND RADAR DETECTOR Detects both LLIST1 12V 15AH AS NEW, £18 REF LOTS radar and laser X K and KA bands, speed cameras, and all known PHASOR BLAST WAVE PISTOL SERIES PLANS THE ULTIMATE ENCLOSURE for your projects must be one speed detection systems 360 degree coverage, front&r Handheld, has large transducer and battery capacity with external of these'Well made ABS screw together beige case measuring 120 earwaveguides, 1 1"x2 7"x4 6" fits on visor or dash £149 controls £6/set Ref F/PSP4 x 150 x 50mm Fitted with rubber feet and front mounted LED Inside CHIEFTAN TANK DOUBLE LASERS 9 WATT+3 INFINITY TRANSMITTER PLANS Telephone line grabber/ is a pcb fitted with other bits and pieces you may find useful Sold as WATT+LASER OPTICS Could be adapted for laser listener long room monitor The ultimate in home/office security and safety' simple a pack of five for £10 ref MD1 .pack of 20 for £19 95 ref MD2 range communications etc Double beam units designed to fit in the gun to use' Call your home or office phone, push a secret tone on your YOUR HOME COULD BE SELF SUFFICENT IN barrel of a tank, each unit has two semi conductor lasers and motor telephone to access either A) On premises sound and voices or B) ELECTRICITY Comprehensive plans with loads of info on drive units for alignement 7 mile range, no circuit diagrams due to Existing conversation with break-in capability for emergency messages designing systems, panels, control electronics etc £7 ref PV1 MOD, new pnee ESO OOO'? us? £199 Each unit has two gallium £7 Ref F/TELEGRAB LOW COST CORDLESS MIC SOC range 90 - 105mhz, 115g, Arsenide injection lasers, 1 x 9 watt, 1 x 3 watt, 900nm wavelength, ELECTROMAGNETIC GUN PLANS Projects a metal object 193 x 26 x 39mm, 9v PP3 battery required £17 ref MAG15P1 28vdc, 600hz pulse frequency The units also contain an electronic a considerable distance-requires adult supervision £5 ref F/EML2 AUTO SUNCHARGER 155x300mm solar panel with diode and receiver to detect reflected signals from targets £199 Ref LOT4 ELECTRIC MAN PLANS, SHOCK PEOPLE WITH THE 3 metre lead fitted with a cigarplug 12v2watt £12.99 REF AUG10P3 MAGNETIC CREDIT CARD READERS AND ENCODING TOUCH OF YOUR HAND! £5/set Ref F/EMA1 SOLAR POWER LAB SPECIAL 2x 6"x6" 6v 130mA cells 4 MANUAL £9.95 Cased with flyleads, designed to read standard 2 FOR 1 MULTIFUNCTIONAL HIGH FREQUENCY AND LEDs, wire, buzzer switch + 1 relay or motor £7.99 REF SA27 credit cards' complete with control elctromcs PCB and manual HIGH DC VOLTAGE. SOLID STATE TESLA COIL AND SOLAR NICAD CHARGERS 4 x AA size £9 99 ref 6P476, 2 x covenng everything you could want to know about whats hidden in that VARIABLE 100,000 VDC OUTPUT GENERATOR PLANS C size £9 99 ref 6P477 magnetic strip on your card' just £9 95 ref BAR31 AIR RIFLES .22 As used by the Chinese army for training, so there EXTERNAL CAMERA introducing the Bulldog model 4 vandal Operates on 9-12vdc, many possible experiments £10 Ref F/HVM7/ resistant camera in heavy steel case for interior or exterior use Top TCL4 is a lot about' £39 95 Ref EF78 500 pellets £4 50 ref EF80 quality case housing a 420 line camera module Each camera is sup- plied with a 15m cable terminating in Scart and phono plugs Multi angle bracket for easy installation In any situation A 12vdc psu is Interactive websites also included Easily installed in a few minutes, plugs straight into VCR or TV (phono or scart) Bargain price £89.95 ref CC1 designed and hosted. 3HP MAINS MOTORS Single phase 240v, brand new, 2 pole, 340x180mm, 2850 rpm, builtm automatice reset overload protector keyed shaft (40x16mm)Made by Leeson £99 each ref LEE1 bullnet.co.uk LOPTX Made by Samsung for colour TV £3 each ref SS52 LAPTOP LCD SCREENS 240x175mm, £12 ref SS51 / PIR WITH BUILT IN CCTV CAMERA Module also includes REGISTER FOR OUR an infra red strobe light, battery backup etc 320x240 pixels, 90x65 COLOUR CCTV VIDEO ELECTRONIC NEWSLETTERS field of view £49 95 ea ref SS81, 3 or more £44 95 ref SS82 WANT TO MAKE SOME MONEY? STUCK FOR AN CAMERAS From £99 BULL-ELECTRICAL.COM IDEA? We have collated 140 business manuals that give you infor- Works with most modern video's, TVs, Composite monitors, mation on setting up different businesses, you peruse these at your video grabber cards. Pal, iv P-P, composite, 75ohm, 1/3" leisure using the text editor on your PC Also included is the certifi- CCD, 4mm F2.8, 500x582, 12vdc, mounting bracket auto BULL ELECTRICAL cate enabling you to reproduce (and sell) the manuals as much as shutter, 100x50x180mm, 3 months warranty,1 off priced 19 250 PORTLAND ROAD, HOVE, SUSSEX . you like' £14 ref EP74 ref XEF150,10 or more £99 ea 100+ £89 HIGH POWER DC MOTORS. PERMANENT MAGNET BN3 5QT. (ESTABLISHED 50 YEARS). 12 - 24v operation probably about 1/4 horse power body measures CIRCUIT PACKS Packs of 35 circuit diagrams covering lasers, MAIL ORDER TERMS: CASH, PO OR CHEQUE 100m x 75mm with a 60mm x 5mm output shaft with a machined flat on SW radios, geigers,bugs,char etc Packl, Pack2, Pack3 £4 99 each it Fixing is simple using the two threaded bolts protruding from the SMOKE ALARMS Mams powered, made by the famous Gent WITH ORDER PLUS £4.00 P&P PLUS VAT. front £22 ref MOT4 company, easy fit next to light fittings power point £4 99 ref SMKX 24 HOUR SERVICE £6.50 PLUS VAT. CONVERT YOUR TV INTO A VGA MONITOR FOR £25! ELECTRONIC SPEED CONTROLLER KIT For the above Converts a colour TV into a basic VGA screen Complete with built in OVERSEAS ORDERS AT COST PIT'S O.SII motor is £19 ref MAG17 Save £5 if you buy them both together, 1 psu, lead and s/ware Ideal for laptops or a cheap upgrade Supplied in (ACCESS,VISA, SWITCH. AMERICAN EXPRESS) motor plus speed controller rrp is £41, offer pnee £36 ref MOT5A kit form for home assembly SALE PRICE £25 REF SA34 'phone orders : 01273 203500 Online *15 WATT FM TRANSMITTER Already assembled but some RF knowledge will be useful for setting up Preamp req'd, 4 stage 80- FAX 01273 323077 108mhz, 12-18vdc, can use ground plane, yagi or dipole £69 ref 1021 web catalogue *4 WATT FM TRANSMITTER KIT Small but powerful FM [email protected] bull-electrical.com ISSN 0262 3617 EVERYDAY PROJECTS . . . THEORY . . . NEWS . . . COMMENT . . , POPULAR FEATURES ...
ELECTRONICS http:/ /www.epemag.wimporne.co.uK | The No. 1 Magazine for Electronics Technology VOL. 27 No. 12 DECEMBER 1998 and Computer Projects
^pteiccls an? (Zivcuiis EPE MIND P/CKLER by Andy Flind 850 Want seven ways to relax? Try our PIC controlled mind machine! FADING CHRISTMAS LIGHTS by Bart Trepak 862 How Seasonal! How Festive! But how different! EV1 HANDHELD FUNCTION GENERATOR by Brian Adkinson 875 Sine, triangle and square wave signals always at hand, with almost full audio range coverage - and output adjustability PhizzyB COMPUTERS - 2 by Clive "Max" Maxfield, Alvin Brown and Alan Winstanley Constructing and testing the Input Switcivand Output L.E.D. Interface boards INGENUITY UNLIMITED hosted by Alan Winstanley 895 Hot Wire Anemometer; Soldering Iron "Ready" Indicator; Lossless Current Sensing; Foghorn Timing Switch DAMP ST AT ELECTRONIC THERMOSTAT by Andy Flind 904 Got rising (or falling) damp? This controller should provide a solution
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NEW TECHNOLOGY UPDATE by Ian Poole 856 "Test tube" takes on a new meaning for microelectronics; Oxygenisation extends chip performance PhizzyB COMPUTERS - 2 by Clive "Max" Maxfield and Alvin Brown 882 Discussing the programming for the Input and Output boards INTERFACE by Robert Penfold 898 Serial L.C.D. Remote Monitor for your PC CIRCUIT SURGERY by Alan Winstanley 900 Null Modems and D-connectors; Pull-ups and Relays; Light-dependent Switch NET WORK - THE INTERNET PAGE surfed by Alan Winstanley 914 EPE Online; Plight of the Navigator; Black Spot; Software Selection
fccgtilats an? J^efoiccs V, * EDITORIAL 847 INNOVATIONS - Barry Fox highlights technology's leading edge 859 Plus everyday news from the world of electronics READOUT John Becker addresses general points arising 871 BACK ISSUES Did you miss these? 874 CD-ROMS FOR ELECTRONICS 892 Parts Gallery + Electronic Circuits and Components: Digital Electronics; plus NEW PICtutor, plus NEW Modular Circuit Design SHOPTALK with David Barrington 902 The essenf/a/guide to component buying for EPE projects ELECTRONICS VIDEOS Our range of educational videos 908 DIRECT BOOK SERVICE 909 * A wide range of technical books available by mail order PRINTED CIRCUIT BOARD SERVICE 912 ' PCBs for EPE projects - some at "knockdown" prices! Plus EPE software ANNUAL INDEX 1998 915 ADVERTISERS INDEX 920 0 Wimborne Publishing Ltd 1998. Copyright in all drawings, photographs and articles published in EVERYDAY PRACTICAL ELECTRONICS is fully FREE protected, and reproduction or imitations in PASSIVE COMPONENTS BOOKLET Cover Mounted whole or in part are expressly forbidden. Our January '99 issue will be published on Friday, 4 Readers Services • Editorial and Advertisement Departments 847 December 1998. See page 843 for details. Everyday Practical Electronics, December 1998 841 Surplus always THE ORIGINAL SURPLUS WONDERLAND! Surplu^lway^l I wanted for cash! I THIS MONTH'S SELECTION FROM OUR VAST EVER CHANGING STOCKS wanted for cashl | THE AMAZING TELEBOX IC S -TRANSISTORS - DIODES 19'' RACK CABINETS Converts your colour monitor Into a QUALiTY COLOUR TV 11 OBSOLETE - SHORT SUPPLY - BULK Superb quality 6 foot 40U 73 6,000,000 items EX STOCK Virtually New, Ultra Smart Less than Half Price! i Top quality 19" rack cabinets made in UK by VIDEO MONITOR SPECIALS Optima Enclosures Ltd. Units feature The TELEBOX is an attractive fulty cased mains powered unit con- One Of the highest Specification III designer, smoked acrylic lockable front door, taining all electronics ready to pluginto a host of video monitors i full height lockable half louvered back door made by makers such as MICROVrTEC, ATARI, SANYO, SONY, ♦ monitors you will ever see - ♦ and louvered removable side panels. Fully COMMODORE, PHIUPS, TATUNG, AMSTRAD etc. The composite At thie 'f it 11 Y; adjustable internal fixing struts, ready punched video output will also plug directly into most video recorders, allowing At this price - Don't miss itlM for any configuration of equipment mounting reception of TV channels not normally receivable on most televi- Mitsubishi FA3415ETKL 14" SVGA Multisync colour monitor with fine plus ready mounted integral 12 way 13 amp sion receivers* (TELEBOX MB). Push button controls on the front 028 dot pitch tube and resolution of 1024 x 768. A socket switched mains distribution strip make panel allow reception of 8 fully tuneable 'off air* UHF colour television variety of inputs alows connection to a host of comput- these racks some of the most versatile we channels. TELEBOX MB covers virtually all television frequencies ers hdudrq IBM PCs h CGA. EGA. VGA & SVGA have ever sold. Racks may be stacked side by side and therefore VHP and UHF including the HYPERBAND as used by most cable modes. BBC, COMMODORE (inducing Amiga 1200), require only two side panels to stand singly or In multiple bays. TV operators. A composite video output is located on the rear panel ARCHMEDES and APPLE Many features: Etched Overall dimensions are: 77V4" H x 32V4" D x 22" W. Order at: for direct connection to most makes of monitor or desktop computer faceplate, text swlching and LOW RADIATION MPR OPT Rack 1 Complete with removable side panels. £345.00 (G) video systems. For complete compatibility - even for monitors with- -.w.— specification. Fully guaranteed, supplied in EXCEL-1 OPT Back 2 Back I occ ciHo nanok nn ins out sound - an integral 4 watt audio amplifier and low level Hi Fi LENT ittte used condition. r\riAnr Over 1000 racks, shelves, accessories audio output are provided as standard. tkiiSwmb.. £4.75 Only £119 (E) ^SSvSa TELEBOX ST for composite video input type monitors £36.95 VGA cat* tar BM PC tndudad. 19" 22" & 24" wide 3 to 46 U high. TELEBOX STL as ST but fitted with integral speaker £39.50 TELEBOX MB Multiband VHFAJHF/Cable/Hyperband tuner £69.95 ExWrWMblM tar oHwlypwotcompuiOT CALL Available from stock !!. For overseas PAL versions state 5.5 or 6 mHz sound specification. As New - Ex Demo For cable / hyperband signal reception Telebox MB should be con- 17' 0.28 SVGA Mitsubishi Diamond Pro monitors nectecUo" a cable type service. Shipping on all Teleboxe's, code (B) 32U - High Quality - All steel RakCab Full multisync etc. Full 90 day guarantee. £325.00 (E) Made by Eurocraft Enclosures Ltd to the highest possible spec, State of the art PAL (UK spec) UHF TV tuner module rack features all steel construction with removable with composite IV pp video & NICAM hi fi stereo sound Just In - Mlcrovitec 20'' VGA (800 x 600 rss.) colour monitors. side, front and back doors. Front and back doors are outoutputs. Micro electronics all on one small PCB only 73 x Good SH condition - from £299 - CALL for Info hinged for easy access and all are lockable with ,&&& 160 x 52 mm enable full software control via a simple 2 wire link PHIUPS HCS35 (same style as CM8833) attractively styled 14" five secure 5 lever barrel locks. The front door ©Sg® to any IBM type computer. Supplied complete withh simpleslmpl working colour monitor with balli RGB and standard composite 15.625 is constructed of double walled steel with a program...am and documentation.^ RequiiRequires Only+12V £49.95& + 5VVDC L. code(B)to operate. Khz video Inputs via SCART socket and separate phono jacks. 'designer style* smoked acrylic front panel to BRAND NEW - Order as MY00. Integral audio power amp and speaker for all audio visual uass enable status indicators to be seen through the Will connect direct to Amiga and Atari BBC computers. Ideal for all panel, yet remain unobtrusive. Internally the rack FLOPPY DISK DRIVES 2'2" - 14" video monitoring / security applications with direct connection features fully slotted reinforced vertical fixing to most colour cameras. High quality with many features such as members to take the heaviest of 19" rack Massive purchases of standard 5!4" and 3V4" drives enables us to front concealed flap controls,rols, VCR correction button etc. Good equipment. The two movable vertical fixing struts present prime product at industry beating low pricesl All units (unless used condition - fully tested - guaranteed (extras available) are pre punched for standard stated) are BRAND N£W or removed from often brand new equip- Dimensions: W14" x H12V x 15V4* D. Only £99 cage nuts'. A mains distribution panel internal- ment and are fully tested, aligned and shipped to you with a full 90 (E) ly mounted to the bottom rear, provides 8 x IEC 3 day guarantee. Call for over 2000 unlisted drives for spares or repair. PHIUPS HCS31 Ultra compact 9" colour video monitor with stan- pin Euro sockets and 1x13 amp 3 pin switched -ss" 3V4" Panasonic JU363/4 720K or equivalent RFE E24.95(B) dard composite 15.625 Khz video input via SCART socket. Ideal utility socket. Overall ventilation is provided by^^ 3V4" Mitsubishi MF355C-L 1.4 Meg. Laptops only E25.95(B) for all monitoring / security applications. High quality, ex-equipment fully louvered back door and double skinned top section 3V4" Mitsubishi MF355C-D. 1.4 Meg. Non laptop £18.95(B fully tested & guaranteed (possible minor screen bums). In attrac- with top and side louvres. The top panel may be removed for fitting 5'/." Teac FD-55GFR 1.2 Meg (for IBM pc's) RFE £18. tive square black plastic case measuring W10' x H10* x 1314" D. of Integral fans to the sub plate etc. Other features include; fitted 5%' Teac FD-55F-03-U 720K 40/80 (for BBC's etc) RFE £29.! 240 V AC mains powered. Qn|y £79_00 (D) 5'/,- BRAND NEW Mitsubishi MF501B 360K £22.S castors and floor levelers. prepunched utility panel at lower rear for Table top case with Integral PSU for HH 514" Ftopp or HD E29.S KME 10" 15M10009 high definition colour monitors with 0.28" dot cable / connector access etc. Supplied in excellent, slightly used 8" Shugart 800/801 8' SS refurbished & tested £2 pitch. Superb clarity and modern styling. condition with keys. Colour Royal blue. External dimensions 8" Shugart 810 8" SS HH Brand New £1 Operates from any 15.625 khz sync RGB video mm«1625H x 635D x 603 W. ( 64" H x 25" D x 23V W ) 8" Shugart 851 8" double sided refurbished & tested £2 source, with RGB analog and composite sync Sold at LESS than a third of makers price II 8- Mitsubishi M2894-€3 double sided NEW £2 such as Atari, Commodore Amiga, Acorn 8" Mitsubishi M2896-83-02U OS slimline NEW £2 Archimedes & BBC. Measures only 1314" x 12" x A superb buy at only £245.00 (G) Dual 8" cased drives with Integral power supply 2Mb £4 11 ".Good used condition. Only £125 (E) 42U version of the above only £345 - CALL HARD DISK DRIVES 20" 22" and 26" AV SPECIALS BATTERY SCOOP - 50% off!! Superbly made UK manufacture. PIL all solid stale colour monitors, 2%' TOSHIBA.(19 mm H ) MK2101 MAN 2.16 Gb. New £199.00 complete with composite video & optional sound input. Attractive A special bulk purchase from a cancelled export order brings you 214" TOSH.(12.5 mm H) MK1002MAV 1.1 Gb laptop. New £115.00 teak style case. Perfect for Schools, Shops, Disco. Clubs, etc.In the most amazing savingsvings on tfthese ultra high... spec 12v DC 14 Ah 214" to 3V4" conversion kit for Pc's. complete with connectors £12.95 EXCELLENT little used condition with full 90 day guarantee. rechargeable)le batteries. Mad"Made by Hawker Energy Ltd, type- SBS15 3V4' FUJI FK-309-26 20mb MFM l/F RFE £59.95 featuring pureure lead plates whichm offer a far superior shelf & jguaran- 3*4" CONNER.e.. CP3024 20 mb IDE l/F (or equiv.) RFE £59.95£69.00 20"....£135 22"....£155 26"....£185(F) yearrear service life. FullyFi BT & BS6290 approved. Si lied 3V4' CONNER™ CP3044 40mb IDE l/F (or equiv.) RFE BRAND NEW and boxed. Dimensions 200 wide, 137 high, 77 314' RODIME R03057S 45mb SCSI l/F (Mac & Acorn) £69.00 DC POWER SUPPLIES M6 bolt terminals.rmir,Ic* FullyCull,# guaranteed.m Current'...rnA makersI.A. pricerL. — over—... £70 3V4" QUANTUM 40S Prodrlve 42mb SCSI l/F, New RFE £49.00 each \Q p j £35 each (q or 4 for £99 m 314" WESTERN DIGFTAL 850mb IDE l/F New £185.00 Virtually every type of power ur r ce 5U" MINISCRIBE 3425 20mb MFM l/F (or equiv.) RFE £49.95 supply you can Imagine.Over 514* SEAGATE ST-238R 30 mb RLL l/F Refurb £69.95 RELAYS - 200.000 FROM STOCK 514" CDC 94205-51 40mb HH MFM l/F RFE tested £69.95 10,000Call Power or sea Supplies our weh Exa It Stocka 514" HP 97548 850 Mb SCSI RFE tested £99.00 Save ££££'8 by choosing your next relay from our Massive 5*' HP C3010 2 Gbyte SCSI differential RFE tested £195.00 LOW COST PC's stocks covering types such as - Military, Octal, Cradle, 8" NEC D2246 85 Mb SMD interface. New £199.00 Hermetically Sealed, Contactors, Tims Daisy, Reed, Mercury 8' FUJITSU M2322K 160Mb SMD l/F RFE tested £195.00 Always over 1000 PC's from stock. Wetted, Solid State, Printed Circuit Mounting, CALL US WITH 8" FUJITSU M2392K 2 Gb SMD l/F RFE tested £345.00 1000'a of spares and accessories. YOUR NEEDS. Many obsolete types from stock. Save ££££'s Call or see our web site for Info. LOW COST RAM & CPU'S TEST EQUIPMENT & SPECIAL INTEREST ITEMS INTEL 'ABOVE' Memory Expansion Board. Full length PC-XT MITS. AFA3445ETKL 14" Industrial spec SVGA monitors £245 Intel SBC 486/125C08 Enhanced Multibus (MSA) NEW £1450 and PC-AT compatible card with 2 Mbytes of memory on board. 1kWto400kW - 400 Hz3 phase power sources-ex stock £POA Zeta 3220-05 AO 4 pen HPGL fast drum plotters £1150 Card is fully selectable for Expanded or Extended (286 processor IBM 8230 Type 1, Token ring base unit driver £760 Nikon HFX-11 (Ephiphot) exposure control unit £1450 and above) memory. Full data and driver disks supplied. RFE. Wayne Kerr RA200 Audio frequency response analyser £2500 Motorola VME Bus Boarirds * &" Components" List. SAE / CALL EPOA Fully tested and guaranteed. Windows compatible. £59.95 IBM 53F5501 Token Ring ICS 20 port lobe modules £750 Trio 0-18 vdc linear, metered 30 amp bench PSU. New Half length 8 Wt memory upgrade cards for PC AT XT expands IBM MAU Token ring distribution panel 8228-23-5050N £95 Fujitsu M3041R 600 LPM band printer £550 memory either 256k or 512k in 64k steps. May also be used to fill AIM 501 Low distortion Oscillator 9Hz to 330Khz. IEEE £550 Fujitsu M3041D 600 LPM printer with network interface £1950 in RAM above 640k DOS limit. Complete with data. ALLGON 8360.11605-1880 MHz hybrid power combiners £250 Perkin Elmer 299B Infrared spectrophotometer A £1250 Order as: XT RAM UG. 256k. £34.95 or 512k £39.95 Trend DSA 274 Data Analyser with G703(2M) 64 i/o £POA Perkln Elmer 597 Infrared spectrophotometer £500 SIMM SPECIALS Marconi 6310 Programmable 2 to 22 GHz sweep generator £6500 VG Electronics 1035 TELETEXT Decoding Margin Meter £3750£3500 1 MB x 9 SIMM 9 chip 120ns Only £8.50 Marconi 2022C 1W
TV ADVERTS TOO LOUD? WE HAVE THE ANSWER. Our Volume Compressor project has been designed with this problem in mind. It can operate as a conventional compressor that responds to the peak level of the input signal, but it also has an "average" mode. In this mode the gain is reduced more on strong signals that have a high average level than it is for signals of equal peak amplitude but a lower average level. With this type of compression the perceived volume of the output signal should remain virtually constant while the input amplitude is above the threshold level.
ALTERNATIVE FROM RUSSIA WITH LOVE? Barry Fox visits a "closed" Russian cosmodrome and COURTESY LIGHT a Moscow rocket factory. Instead of building CONTROLLER intercontinental ballistic missiles, Russia is now This neat little unit provides a delayed helping to put American communications satellites switching off action for a vehicle's into orbit. The Russian Baikonur Cosmodrome was headlights. Once you lock and leave your built in 1955 and covers 7,000 square kilometres. For car, its headlights will light the way to the years Baikonur was not marked on any map, and front door or out of your garage. With two then it was deliberately marked in the wrong place. quick and easy setting modes the unit Whilst still a closed area, Barry has paid an "official" requires no extra dashboard switches. visit and his report makes interesting reading.
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EVERYDAY DON'T MISS AN ISSUE - PLACE YOUR ORDER NOW! PRACTICAL JANUARY ISSUE ON SALE ELECTRONICS FRIDAY, DECEMBER 4 Everyday Practical Electronics, December 1998 843 PIC BASIC COMPILER Crownhill Associates Limited Write PIC Programs in BASIC • Expanded BASIC Stamp I compatible instruction set • True compiler provides faster program execution PIC12C508/509 DEVELOPMENT SYSTEM and longer programs than BASIC interpreters This integrated development environment offers a • I2CIN and I2COUT instructions to access external unique software development tool for the PIC serial EEPROMs and other I2C devices 12C508 / 509. The package consists of 508/509 • More user variables In-Circuit Emulator, Programmer, EdICE a fully • Peek and Poke instructions to access any PIC integrated Assembler with trace functions & ICE508 register from BASIC tracer/disassembler. • Serial speeds to 9600 baud The development system is supplied with MPASM • In-line assembler and Call support Universal PIC CHIP • Supports all most popular PICs. PIC16C55x, 6x, programmer supports the assembler/disassembler and 10 projects, including 7x. 8x. 92x and PIC 14000 micros following Microchip circuit diagrams and unprotected source code. Projects • Use with any PIC programmer devices cover subjects from simple sound effect generator Write your PIC programs in BASIC! The PicBasic PIC16C52, PIC16C54, through to an accurate Digital Volt Meter, Smoke Alarm, Compiler converts BASIC programs into hex or binary PIC16C55. PIC16C56, Stop Watch, LCD display driver, Keypad encoder and more files that can be programmed directly into a PIC PIC16C57, PIC16C58A, Price £59.95 + 7.50 P&P+ VAT microcontroller. The easy-to-use BASIC language makes PIC programming available to everyone with PIC16C61, PIC16C62, its English-like instruction set. Supplied with Universal PIC CHIP Programmer, connects to Parallel port of PC and programs all NEW! PIC PROGRAMMER KIT popular PIC micros. Complete with programming Programs the Popular PIC 16C84, 16F84, 12C508/9 and 24xx series serial memory toolkit - Editor. Assembler & Programming software. devices. Connects to the serial port of a PC and requires No EXTERNAL power supply. The kit includes instructions for assembly, circuit diagram and component layout. PIC BASIC PRO This handy little programmer is easy to build, taking no more than 30 The PicBasic Pro Compiler allows BASIC Stamp II PIC16C63. PIC16C64, mins. to assemble and test. The Professional quality PCB is commands, using pins on PORTA. C. D. E, as well as PIC16C65. PIC16C620. double-sided, throuqh-plated with solder resist and screen printing to PORTB, and the capability of using more RAM and PIC16C621. PIC16C622. aid efficient assembly. It is supplied with driver software to run in program space. PIC16C71. PIC16C73, DOS on a 286 PC upwards and under Windows 95 on 486 or A list of the new features and commands appear below. PIC16C74, PIC16C84, Pentium and a Disk full of interesting projects, tips and data sheets • Real If. .. Then . . Else . .. Endif PIC16C622. PIC16F84, for PIC devices, including FREE Assembler and Simulator (requires • Hierarchical expression handling PIC16F83, PIC16C554, 9-pin D-type to 9-pin D-type cable to connect to serial port of PC) • Interrupts in Basic and assembler PIC14000. PIC16C508, CABLE £5 INC. VAT AND DELIVERY. COMPLETE KIT just £15.00 including Delivery and • Bult-in LCD support PIC 12C509. & MEMORY VAT (UK Only). Or READY BUILT £20.00 INCLUDING Delivery and VAT (UK ONLY) • Oscillator support from 3-56Mhz to 20Mhz CHIP24C01 TO 24LC65 • More variable space (processor dependent) • MPASM/ICE compatibility Price £49.95 * P&P + VAT • All Assembly routine for all functions are supplied 1998 Microchip PIC16C84 04p PIC 12C508/509 DIL and can be modified to suit your needs I-10 £2.00 I-10 £1.05 Supplied with sample programs including circuit diagrams CD ROM II-100 £1.90 II-50 £1.00 PIC BASIC without programmer or PIC84 £49.95 + 5.00 P&P + VAT • Packed with information 101-500 £1.80 51-100 £0.90 PACKAGE with programmer & PIC 16x84 £99.95 + 5.00 P&P +VAT • All current data sheets PIC BASIC PRO without programmer or PIC16F84 £150.00 + 5.00 P&P + VAT • Programs and Diagrams 24LC16 24LC65 PIC BASIC PRO with programmer and PIC 16F84 £ 198.00 + 5.00 P&P + VAT • Application notes 1-50 £1.00 1-50 £1,50 • PDF Viewer http://www.crownhill.co.uk/picbasic £10 inc. VAT P&P (in UK) PIC16C620 £1.95 PIC16C621 £2.25 PIC16C622 £2.50 The Old Bakery, New Barns Road, Ely, Cambs AMAZING LOW PRICES PIC Prices + P&P VAT A Tel: 01353 666709 Fax: 01353 666710 PIC 84 & MEMORY email: [email protected] http://www.crownhill.co.uk
HOW DOES YOUR EQUIPMENT MEASURE UP? AT STEWART OF READING THERE'S ALWAYS 'SCOPE' FOR IMPROVEMENT! PHILIPS PM3217- The s realty a PHILIPS PM3296A dual trace 400MHz dual TB delay cursors Dual Trace 50MHz Delay very good IEEE - £2250 SPECTRUM ANALYSERS —LOOK!!! —— TEKTRONIC 2465A 4-ch dual trace 350MH2 delay sweep cursors H.P. 8562A synthesised 1 KHz-22GHz £10.000 BRAND NEW OSCILLOSCOPES - NEVER USED - LIMITED STOCK including 2 probes. etc £2500 H.P. 8565A 001 -22GHz £3500 Pooch & Front TEKTRONIX 2445 2445A0 4-ch, 150MHz delay sweep cursors H.P. 8590A IOKHz-1 -BGHz (75 ohms) £2500 cover etc ...... From £900 H.P. 8559A with mam frame OOI -21 GHz £2500 DMS 3850A Digital TEKTRONIX TAS465 dual trace 100MHz delay cursors £900 H.P. 8558B with mam frame 100KH2-1500MHz £1500 Storage DMM ONLY 4 TEKTRONIX 2235 dual trace 100MHz delay cursors £700 ADVANTESTTR4131 10KHZ-3-5GH2 £3500 Handheld LCD display. 2 chan- IWATSU SS5711 4-ch 100MHz delay sweep £550 ADVANTESTTR4132 100KHz iGhz £1200 Inel 50ms/s, auto range. 4-digit GOULD OS300 Dual PHILIPS 3055 2 + 1-ch 50MHz dual 11 £475 MARCONI 2382 100HZ-400MH2 htgh resolution £1200 iDMMcapacitancelrequency counter, Trace 20MH2 MARCONI 2370 30Hz 110MHz From £500 battery operation or external 7-5V-9-5V d c.. i.e. a.c. adaptor (not Ught weight Very good H.P.141 Systems: supplied), RS232, comes m WacK carrying pouch complete with 2 value - NOW THIS IS RIDICULOUS! 85548553 500KHZ-1250MHzIKHz-110MHz From £750£500 scope probes. DMM leads Manual FOR ONLY £400 ONLY 8555 10MHz-18GHz From £1000 BTS 40 Digital p" " ^4^"' .A.**A0 ft***,!!' THIS IS THE - - | j FARNELL LF1 Sine Sq Oscillator Storage BEST CHEAP ^ •/J-^Wy SCOPE Dual Trace 40MHz, 20ms's storage, cursors and on-screen ■ ft YOU WILL LEVELLTG200DMPRC1 Hz-1 MHz Sine/Square, meter.Oscillator w readout, sweep delay, mterface etc., etc Supplied unused in . EVER BUY!!! battery operated (Batteries not supplied) original box complele with 2 probes and manual A ^ AMAZING VALUE AT £400 GOULD 0S1100 - Dual Trace, 30MHz MARCONI 2019 synthesised AM/FM Classic AVO Meter Delay Very bright, supplied with signal gen 80kHz-1040MHz, l.c.d. A Digital AVO DA116 3-5 digit DTA 20 manual and two probes display, keyboard entry only *4^ Complete with Batteries & Leads Dual Trace TEKTRONIX 2215 - Dual Trace 60MHz ONLY 20MHz MARCONI 2017 phase lock AHAFM stoial gen IDkHz ,-♦» Sweep Delay MARCONI1024MH2 2022A/C synthesised AMFV signal generator tOKHz£1200 Alt Mag TV Trig etc. Unused & Boxed with Includes 2 probes 1GHz From £1500 METROHM 9A — 500V Battery 2 probes and manual ONLY H.P.8672A synthesised signal generator 2-18 GHz £6000 Meggar (a useful back-up for fault finding) Complete with Batteries & E u .UT-lwU • & U-JL-J Leads ONLY ti-. I TEKTRONIX 400 SERIES lOOKHz-100MHz, FMO-IOOKHz: Output - l9dB-99dB AM0-60% Solatron 7045 - 4 5 Dig. Bench 32 preset memory; digital display frequency and output -y-tS'glP "if wA mmmmmmmmm Multimeter with leads Used £450 Unused £750 KENWOOD Solatron 7150 DDMM 6-5 digit FL180A WOW/FLUTTER METER. a H.P. 8640A AM/FM Signal Gen f 0-003V10%: treq 3kHz/3-l5kHz i True RMS ; RMS'AVERAGEREAK 500kHz-1024MHz-Audio Option ^ IEEE ' Weighted Fillers, Digital Display of 468 Digital Storage Dual Trace 100MHz Delay £550 FARNELL SSG1000 syn AMTM signal gen 10KHz-lGHz.. £995 -j WAYNE KERR AMM255 , i-" Unused CSMI 9rpm,"* 4-digiiHO0' 0Freq'kH' Counter55kH! 0-0lKHz- 466 Analogue Storage Dual Trace lOOMHz Delay £250 FARNELL PSG520 syn AM/FM sw gen 10KHz-520MHz port £450 Automaticinlesm-st.k- Modulation llAtneMeter UbeOUsK £M0INW, UIUSCU LDUU 475485 Dual Trace 200MHz350MHz Delay Sweep £750 RACAL 9081 syn Am/FM sig gen 5-520MHZ £400 AM'FM 15MHZ-2GHZ 35 digit 465 Dual Trace lOOMHz De'ay Sweep £450 MARCONI TF2015 AMfFM sig gen 5 520MHz £175 POWER SUPPLY Model HSP3010, 0-30V £350 MARCONI 6311 programmable sweep gen 10MHz-20GHz £4000 Unused <22) 0-10 Amps current limiting. HP 3325A syn (unction gen 21 MHz £950 2 meters HC3502 Dual Trace 20MHz 5mv-20v/i>v.secs-0-5 SecDrv; o-2u PHILIPS PM5134 sweep function gen 0-001Hz-20MHz £300 GOODWILL GFC 8010G Used £160 Unused £200 X-Y: X5 Magnifier MARCONIPHILIPS PM5132 2305 modulation sweep func meter gen 0-1Hz-2MHz500KHz-2GH2 From £1200£200 FREQUENCY COUNTER, Range TV Sync etc. FARNELL AMM2000 automatic mod meter 10Hz-2'4GHz, 1HZ-120MHZ, 8-Digit Display. l5mV GOODWILL unused £1250 RMS Sensitivity Unused £75 GVT427 DUAL CHANNEL A C JNUSED 844 Everyday Practical Electronics, December 1998 Easy-PC Electronics CAD for Windows 95, 98 and NT True Windows graphical user interface r.-arxi i» w mb <*>cy Multi-sheet Schematics - Projects. New, Sub-circuit re-use facility allows copying of myiHil l i'/II sections of designs from proven projects Now with Multiple level Undo / Re-do. Full links to our Analogue, Digital and Electromagnetic Simulators. Impressive, high speed, gridless, shape-based vcc autorouter options Full Design rule and connectivity checks. Full Wndows outputs. Gerber, Excellon and DXF outputs CLR NO Free technical support! No dongles or maintenance R-C contracts. CE GND Trade up allowance from other products. Entry level version available. New Demo' available - please call. No Quibble 30 Day Money back Guarantee Number One Systems Ref: EVD, Harding Way, Sl.lves, Cambridgeshire, PE17 4WR, United Kingdom Tel: 01480 461778 Fax: 01480 494042 ±n International: +44 1480 461778/494042 Wffc - email: [email protected] http://www.numberone.com Overseas dealer enquiries welcome jyym/iLsi I eG aS t Sti [L^annnr / IW ^/A\l QUALITY SURPUUS STOCK AND ALL AT THE LOWEST PRICES! S&E3S PHONE, FAX OR TR0 c < 0 P0 f7^ R "' : : ™ "TZ^ WRITE TODAY FOR 2/D Park Road • Southampton • S015 3UQ TELEPHONE: 01703 236363 FAX: 01703 236307 VnilR PBFF TOPYf E-Mail: greenweldi"aol.com INTERNET: http://www.greenweld.co.uk I V/wll I Tltt W\/l • ■ Everyday Practical Electronics, December 1998 845 TT98 RF Connectors Push Switches,, Boxes A Cases Equipment Wire Many mor^jzes available Colours Black, Brown, Red Orange, Yellow, Green. Blue. Purple, Grey & Wnite BNC Plug 50Q Solder £0.93 Miniature Round Per fOOm Reel BNC Plug 50ii Crimp £0.62 250mA 125V 28 x 10mm Solid 1/0.6mm £2.72 BNC Plug 75fl Solder £0.95 7mm 0 Mounting Hole Stranded 7/0.2mm £2.53 HI. I MIC COMPOMEMTS BNC Plug 75Q Crimp £0.70 Non Latching Push to Make Opto Electronics §55 BNC Chassis Socket £0.83 Black_PTM £0.24 General Purpose Plastic LIDS F Plug - Twist £0.24 Red PTM £0.24 75 x 56 x 25mm £0.93 3mm Red Led £0.08 F Plug - Crimp £0.26 Yellow PTM £0.24 75 x 51 x 22mm 3mm Green Led £0.09 TNC Plug 50Q Solder £124 Green PTM £0.24 111 x 57 x 22mm ci£0.93 3mm Yelow Led £0.10 Station Road, Cullorceats, TNC Plug 50*2 Crimp £0.85 Blue PTM £0.24 79 x 61 x 40mm cicQ 3mm Orange Led £0.10 55 TNC Plug 75*2 Solder £1.40 White PTM £0.24 100 x 76 x 41mm cixo 5mm Red Led £0.08 Tyno A Woar, NE30 4PQ TNC Plug 75*2 Crimp £1.16 Non Latching Push to Break Il8 x98 x45mn ci ol 5mm Green Led £0.10 UHF Plug 5mm Cable ^£0.63 Black PTB a £0.24 150 : 100 x 60mm £2.65co xs 5mm Yelow Led £0.10 ■to UHF Plug 11mm Cable £0.83 Standard Square 150- _ < 80 x 50m £2.47 5mm Orange Led £0.10 B & sz r r UHF Chassis Skf- Sqr £0.50 Diecast Aluminium 5mm Red Flashing £0.44 All Major Credit cards Accepted zl UHF Chassis Skt- Rnd £0.73 50 x 50 x 31 mm co ox 5mm Green Flashing £0.50 Extensive range of RF con- 1A 250V co oq 5mm Yellow Flashing £0.54 Prices Exclude Vat @17^%. Add £1.25 carriage nectors in stock, inc.FME, 100 x 50 x 25mm - - - - 5mm Bi-Colour Led £0.33 & Vat to all orders. Cheques / Postal orders ®8 SMA, Mini UHF & N Type. 39xl5MMkJj>'12mm 0 Mourttifia Hole 120112 x 6562 x 40mm3131mm mm £3.55£4.19 5mm Tri-Colour Led £0.28 able to ESR Electronic Components Non Latching Push to Make 150 x80 x50mm £5.36 7 Segment Displays Sockets D Type Connectors Terminals Black PTM £0.60 121 x 95 x 61mm £5.99 0.56" Red C.Cathode- £0.78 Red PTM £0.60 Two Piece Aluminium 0.51" Red C.Anode £0 78 Blue PTM £0.60 133 x 70 x 37mm 0.3" Red C.Cathode £0.78 White PTM £0.60 102 x 102 x37mm n£2.08 oa 0.3", C.Anode £0.78 Colours Red, Black, Green, Latching -push On push Off 102 x 70 x 37mm £ Infra Hud Devices Stamped Pin Solder Bucket Blue, White or Yellow Black £0.65 133 x 102 x 37mm pl sQ 3mm IR Emitter £0.23 6 Pin OIL 0.3" £0.06 9 Way Male Plug CO.29 2mm Solder .Plug ,w £0.18 Red £0.65 102 x 63 x 50mm of qT 5mm IR Emitter £0.39 8 Pin DIL 0.3" £0.06 ? Way Female Socket £0.28 2mm Chassis Sockets £0.26 Blue £0.65 76 x 51 x 25mm 3mm Photo-Transistor £0.26 14 Pin DIL 0.3" £0.11 15 Way Male Plug ^0 39 4mm Solder Plugs £0.30 White £0.65 152 x 102 x50mm co on p5mm Photo-Transistor £0.64 16 Pin DIL 0.3" £0.11 15 Way Female Socket £0,39 4rnrn4mm Stackable Plugs 178 x 127 x 63mm coxo 4N25hoto Diode £0.75 18 Pin DIL 0.3" £0.12 15 Way H.D. Plug Chassis Sockets £0 23 Rocker -Switches_ 203 x 152 x 76mm 4 Opto-Coupler £0.38 20 Pin DIL 0.3" £0.11 15 Way H.D. Socket £0.78 4mm Binding Posts tu.af£0^54 >a'Hca\/Miniature5 V cS u d r t 102 x 102 x 63mm £ -?° 4N26 Opto-Coupler £0.36 24 Pin DIL 0.6" £0.13 23 Way Male Plug £0.49 33™ Crocodile Clips £0.13 lpc? ^ Y fl ® J°9f 133 x 102 x 63mm S I? 4N32 Opto-Coupler £0.45 28 Pin DIL 0.6" £0.13 23 Way Female Socket£0.49 spstSPST 21/i x* 14 xy 16mmlAmm £0.69 152 x 102 x 76mm coE3 23oo 6N135 Opto-Coupler £1.30 40 Pin DIL 0.6" £0.19 25 Way Male Plu £0 46 Power Connectors J DPDT21 x 24 x 22mm £0.96 Stool/Aluminium - 6N136 Opto-Coupler £0.85 Turned Pin 25 Way Female Plug £0*41 DC Low Voltage^ SPST-Red Neon £1.02 Plastic coatod stool top. 6N137 Opto-Coupler £0.90 8 Pin DIL 0.3" £0.11 IDC Ribbonon Mounting SPST - Green Neon £1.02 Aluminium base 6N138 Opto-Coupler £1.30 14 Pin DIL 0.3" £0.20 9 Way Male Plug 0.08 SPST - Amber Neon £1.02 152 x 114 x 44mm Cx 10 6N139 Opto-Coupler £0.90 16 Pin DIL 0.3" £0.23 9 Way FemgleJSocket £1.08 DC 3 0 ^ 2 350D £0 46 15A 250v push on T 203 x 127 x 51mm cloo CNY17-1 O-Coupler £0.47 18 Pin DIL 0.3" £0.26 25 Way Male Plug a,..iwtj.jo D nr- i oiR^ o £0 32 SPST 30 x 11 x 22mm £0.62 Si ll CNY] 7-7 O-Coupler £0.38 20 Pin DIL 0.3" £0.28 25 Wav Female Socket£l 13 C Plug 1-3ID 3.40D 229 x 127 x 63mm £3 04 CNY17-3 O-Coupler £0.47 24 Pin DIL 0.6" £0.35 Right Waled9 PCB DC Plug 1,710 4.0OD £0.50 DPDT 30 x 25 x 22mm £1.12 114 x 63 x 57mm IS-74 Opto-Coupler £0.45 28 Pin DIL 0.6" £0.41 DC Plug 1.710 4.750D £0.46 Illuminated Wire A Cable ISD-74 Opto-Coupler £0.99 40 Pin DIL 0.6" £0.64 DC Plug 2,)ID 5.0OD £0.24 15A 250V Push on Tags Ribbon Cablo ISQ-74 Opto-Coupler £1.52 SIL Pin Header Strip DC Plug 2.5ID 5.0OD £0.24 SPST 30x14mm Red £0.84 Price per 300mm (1ft) MOC3020 Opto-Triac£0.68 1 x 36 Way Straight £(T38 DC Plug 3.1ID 6,30D £0.46 DPST 30x25mm Red £1.40 10 Way Grey Ribbon £0.11 MOC3041 Opto-Triac£0.96 2 x 36 Way Straight £0.56 DC Line06 Socket 2.1 mm £0.64 DPST 30x25mm Amber£l .40 16 Way Grey Ribbon £0.17 ORP12 LDR £0.89 1 x 36 Way 90 £0.54 9 Way Male Plugh £0 37 ^ L' Socket 2.5mm £0.56 DPST 30x25mm Green£1.40 20 Way Grey Ribbon £0.22 Selar Cells 2 x 36 Way 90 £0.80 9 Way Female^ Socketocket. . £0£0.35£(T35 77 "JxDC ^"assisChassis Sktbxr 2.5mm2.1i mm £0.46tu.46 pprRfJ,Ree|iavsavl 26 Way Grey Ribbon £0.28 0.45V Screw Terminals Available in 2,3.4,5 & 10 15 Way H.D. Socket tw.//~X ^ IECISr Meet... AA OAAVeem rLUM < n 434in Way' Greyr* Ribbonn-i i £0.38~r\ in OnA—100mA A 26OC x.. 46mmC/ £0.85 way. Also female PCB 25 Way Male Plug £0.53 Mains 6A 250Vac 1A 24Vdc DP?)T 5V £1 44 0 Way Greyrey Ribbon £0.48 200mA 35 x 56mm £1.19 socxets & jumper links. 25 Way Female Socket £0.51 lA24Vdc DPDT 12V fMO 5S ^ p en S 800mA 66 !! 95mm £1.70 20 Way Socket Strip£0.54 Plastic D Covers _ 3A 110V SPDT 6V £0.58 £0 Way Grey Ribbon £0.64 800mA 66 x 95mm £2.96 Transistor Sockets 9 Way Cover - Grey £0.30 3A 110V SPDT 12V en Enamelled>er 2oz Copper fnrIre 1000mA 76 x 95mm £3.52 T018-4 Base Socket £0.24 9 Way Cover - Blacx £0.30 5A 110V SPDT 6V £0 72 ' C ) Reel Crystals 15 Way Cover - Grey £0 33 5A 110V SPDT 12V £0 72 ^OOg4 reels available .. -. DT-38 Small Can T05 Base Socket £0.24 23 Way Cover - Grey £0 36 3 Pin IEC Lme Socket £1.14 5A HOV DPDT 6V £0 93 I ^WG Enamelled £0.95 32.768KHz £0.42 IDC Cable Sockets 23 Way Cover - Black £0 36 3 Pin IEC Line Plug £1.83 5A 110V DPDT 12V £0 93 SWG Enamelled £0.95 HC-49/U Case 25 Way Cover - Grey £0.36 3 Pm Chassis Socket £0.56 5A 240V DPDT 6V pV yz 18 SWG Enamelled £0 95 1.8432MHZ £1.49 """- ay "- - Block £0.36 83 Pm Chassis Plug £0.72 5A 240V DPDT 12V ei 'yz 20 SWG Enamelled £0 95 2.0MHZ £1.49 9 to 9 Lover / Case £0 96 Way Bulgin 10A 240V SPDT 6V e n? 22 SWG Enamelled £0.?9 2.4576MHz £1.24 25 to 25 Cover / Case £0.84 10A 240V SPDT 12V £1 44 24 SWG Enamelled £ ■ 0 3.2768MHz £0.96 10 Way Socket £0.23 9 to 25 Cover / Case £0.96 10A 240V SPDT 24V £1 44 26 SWG Enamelled £ 2 3.579545MHz £0.81 14 Way Socket £0.34 Audio Connecters 28 SWG Enamelled CJ-jS 3.6864MHz £0.81 16 Way Socket £0.31 Computer Accessories 30 SWG Enamelled £ gO2 4.0MHz £081 20 Way Socket £0.26 Adaptan^ 32 SWG Enamelled £ 24g 4.194304MHz £0.81 26 Way Socket £0.35 cm^ He 34 SWG Enamelled £]- 4.433619MHz £0.81 34 Way Socket £0.52 2,5mm Jack Plug £0.21 g pin Chassis^kl5?^ £4.08 36 SWG Enamelled £1.25 4.9152MHz £0.81 40 Way Socket £0.66 2.5mm Line Socket £0.16. . £1.39 38 SWG Enamelled £1.50 6.0MHz £0.81 50 Way Socket £0.75 2.5mm Chassis Socket £0.09 Toggle 40 SWG Enamelled £1.81 6.144MHz £0.81 PCB Bex 3.5mm Mono Plug £0.24 Swlfches Tinnod Copper Wire 7.3728MHz £0.81 Headers 3.5mm Mono Line Skt £0.30 9M Gender Changer £2.18 Per 50g (2oz) Reel 8.0MHz £0.81 3.5mm Mono Chassis £0.14 9F.. Gender Changer £2.2? 500gUq reereels available --- 8.867238MHz £0.81 3.5mm Stereo Plug £0.33 25M Gender Changer £2.60 16 SwG Tinned £0-95 10.0MHz £0.81 3.5mm Stereo Line Skt £0.37 25F Gender Changer £2.80 18 SWG Tinned £095 n.OMHz £0.81 10 Way Straight £0.27 3.5mm Stereo Chassis £0 34 Sub-Miniature 9 Male - 25 Femafe £1.90 20 SWG Tinned £0-99 ii.0592MHz £0.83 14 Way Straight £0.36 VS Mono Plug £0,30 3A 125V 1A 250V 9 Female - 25 Male £1.90 22 SWG Tinned £099 12.0MHz £0.83 16 Way Straight £0.36 %" Mono Line Socket £0 35 5mm 0 Mounting Hole 9M - 6 Mini Din Male £2.40 24 SWG Tinned £1 01 14.7456MHz £0.83 20 Way Straight £0.41 !4* Mono Chassis Sk £0 40 SPST 5 x 10mm £0.58 9F - 6 Mini Din Female£2.40 Continued... 16.0MHz £0.83 26 Way Straight £0.57 14* Stereo Plug £040 SPDT 5 x 10mm £0.60 5M Din - 6F Mini Din £2.08 20.0MHz £0.90 34 Way Straight £0.57 14" Stereo Line Socket £0 38 SPDT C/Off 5 x 10mm £0.86 5F Din - 6M Mini Din £2.08 40 Way Straight £0.63 Y*" Stereo Chassis Skt £0 40 DPDT 9.2 x 10mm £0.66 Testers / Patch Boxes EVERDAY PRACTICAL ELECTRONICS PROJECTS 50 Way Straight £0.96 niutkik Speakon Plugy £2 65 M'^Udyr? Mini Tester 7 LEDs £6.68 Discounted Component Kits Now Available 10 Way 90 £0.33 DIN Series xato^/qa6A 125V 3A 250V Check Tester+ 18 LEDs £6.98 Full details on our Web site. 16 Way 90 £0.42 2 Pin Line Plug £0 21 6.2mm 0 Mounting Hole Enhanced + Switches US./S£15.25 htfp://www.esr.co.uk 20 Way 90 £0.53 2 Pin Chassis Socket laiS SPST 8 x 13mm £0.70#ti %%25D Jumper Box M-F £2.90 Pulsed Peizo Sounder 26 Way 90 £0.70 3 Pin Line Plug £0 27 SPDT 8 x 13mm ftwX 25D Patch Box M-F £7.32 High output peizo sounder with flying leads, built in 34 Way 90 £0.72 3 Pin Chassis Socket £0 28 SPDT c/off 8 x 13m £0 60 Anti-Static Wrist Strap £4.76 driver & pulsed circuit. 40 Way 90 £0.83 4 Pin Line Plug £0.24 SPDT c/o Biased 2 nv£l 10 RS232a ns Surge Protector £5.43 3-20Vdc, 18mA, 50 Way 90 £0.95 4 Pin Chassis" iocket £0^26 SPDT c/o Biased 1 woy£1.64avEl 04 ^ ' Surge Protector£l 1.99 85dB (Min 9Vdc), 42mm0. £0:30 DPDT 12 x ]3mm^ £0.72 i Gofg Surge Block £15.50 PCB Latch 5 Pin Chassis bkt 180" £0.33 DPDT c/off 12 x 13mm £0.80 £0.85 ea, Headers 5 Pin Line Plua 240 £0.24 DPDT c/o Biased 2 way£l .28 5 Pin Chassis okf 240" £0.32 DPDT c/o Biased 1 way£1.28 £0.79 (25 + ) 5 Pin Line Plug 360 £0,24 Normal Price £1.60 5 Pin Chassis Ski 360" £0.32 OA 250V Push on terminals DM830 Digital Multimeter 6' Pin Line Plug £0 27 11 mm 0 Mounting Hole A sturdy well designed 37? Digit LCD multimeter ideal for 10 Way Straight £0.50 6 Pin Chassisbocket £0 35 SPST 18 x 30mm £1.44 1.5m Printer L hobby or professional use. Covering five functions with 16 Way Straight £0.70 7 Pin Line Plug £0.35 SPDT 18 x 30mm £1.42 5m Printer Lead £9.38 18 range including lOAdc Current - "DC Volts, AC Volts, 20 Way Straight £0.78 7 Pin Chassis Socket £0 37 SPDT c/off 18 x 30mm £1.52 10m Printer Lead £8.75 DC Current, Resistance, Diode Test, also with simple 26 Way Straight £0.81 8 Pin Line Plug XX£0'44 o7 norvrDPDT ,./««21 x m30mm ^ £1.78^ Serial Printer 25M-9F £4.50 function generator output. Supplied complete with bat- 34 Way Straight £0.86 8 Pin Chassis Socket £0!36 DPDT c/off 21 x 30mm £1.78 Serial Printer 25M-25F £4.45 tery, test leads & operating instructions. CE Approved. 40 Way Straight £1.56 Phono Series Slide Switches Null Modem Leads 50 Way Straight £1.29 9 Female - 9 Female £3.45 10 Way 90° £0.58 25 Female- 25 Female £4.63 16 Way 90" £0.78 9 Female - 25 Female £2.90 20 Way 90° £0.82 Red Line Plug £0.20 „ 9&25F to 9&25F £5.54 26 Way 90° £1.06 Black Line Plug £0 20 Miniature Modem Loads 34 Way 90" £1.14 Yellow Line Plug £0,20 300mA 125V 25Male to 9Female £4.08 40 Way 90" £1.26 White Line Plug £0.20 7 x 15mm Mounting Hole 25Male to 25Female £4.75 50 Way 90° £1.74 Red Line Socket PC Link Leads Black Line Socket £0SS 2220 StandardDPDT 7 x 23mm £0.20 Interlink 25M to 25M OIL Headers Yellow Line Socket £0.20 1A 125V Patch Lead £4.38 White Line Socket £0-20 5.5 x 12mm Mounting Hole 25Male to 25Male £4.12 Red Chassis Socket 2222 DPDT 12 x 35mm £0.24 36Male to 36Male £5.90 Black Chassis Socket DPDT c/o 12 x 35mm £0 27 Internal Leads Gold Plated Plug Red £0 76 - Floppy Cable A/B £2.99 AC Volts i 14 Way DIL^^^ £0.54 Goid Hated Hug BiackEOV/, "otary Switches HardDisk 2xlDE £1.65 0-200-750V \ 16 Way DIL £0.59 XLR Series - metal — Power 372-2 x 316 £1.88 DC Volts 24 Way DIL £0.90 Power 5J4-2 x 5% £1.50 0-200mV-2-20-200-l 000V 40 Way DIL £1.02 Power 5%-2 x 316 £2.24 DC Current Translstion Headers Power 514-316,514 £2.24 0-200/iA-2-20-200mA-l OA 10 Way Transistion £0.49 Netwerkinq Resistance 14 Way Transistion £0.47 3 Pin Line Plug BNC T Piece TMF £2.40 0-200*i:2-20-200k*l-2M*i 16 Way Transistion £0.47 3 Pin Line Socket li io 150mA 250V • BNC T Piece FFF £2.40 Dimensions 126 x 70 x 24mm 20 Way Transistion £0.54 3 Pin Chassis Plug £1.50 Make before Break 22m 0 BNC Coupler F £1.02 26 Way Transistion £0.62 3 Pin Chassis Socket £141 9.8mm6 0 Mounting Hole BNC Coupler M £1.65 34 Way Transistion £0.67 Neutrik Line Plug £1 73 1 Re' 12 Way £0.84 BNC Ratchet:net Crimp',Crimper£l 7.44 PCB Material 8 Equipment Neutrik Line Socket J32 Pale0 ee 64 Way £0.84 £1.24 40 Way Transistion £0.90 Neutrik Chassis PluiPlug £2.1 3 4 ro 3* way £0.84 50p BNC Terminator FREE Fully illustrated catalogue, send SAE (60p Stamps) 50 Way Transistion £1.02 Neutrik Chassis SQcl£et£2.32£2.13 A ° ' WayMay £0.84 Thinnet Cable per m £0.39 Tel: 0191 2514363 Fax: 0191 2522296 Email: [email protected] Mtp://www.esr.co.uk Everyday Practical Electronics. November 1998 Editorial Offices: EVERYDAY EVERYDAY PRACTICAL ELECTRONICS EDITORIAL ALLEN HOUSE, EAST BOROUGH, WIMBORNE DORSET BH21 1PF Phone: Wimborne (01202) 881749 Fax: (01202) 841692. Due to the cost we cannot reply to overseas orders or queries by Fax. E-mail: editoriakSepemag,wimborne.co.uk Web Site: http://www.epemag.wimborne.co.uk See notes on Readers' Enquiries below - we regret lengthy ELECTRONICS technical enquiries cannot be answered over the telephone. Advertisement Offices; EVERYDAY PRACTICAL ELECTRONICS ADVERTISEMENTS MILL LODGE, MILL LANE THORPE-LE-SOKEN, ESSEX C016 OED VOL. 27 No. 12 DECEMBER '98 Phone/Fax: (01255) 861161 WAY OUT IN FRONT Editor: MIKE KENWARD It's good to know that all our efforts to provide an exciting, technically informative, Secretary: PAM BROWN value for money publication each month are being rewarded by an increase in our UK Deputy Editor: DAVID BARRINGTON newsstand market share. EPE now has over fifty-five per cent of the total UK "elec- Technical Editor: JOHN BECKER tronics hobbyist market", with three other publications making up the remaining On-Line Editor: ALAN WINSTANLEY forty-five per cent between them. In fact, we sell over twice as many copies on the UK Business Manager: DAVID J. LEAVER newsstands than any other magazine in this market, so, hopefully, we are doing Subscriptions: MARILYN GOLDBERG something right. Editorial: Wimborne (01202) 881749 Far from seeing a decline in interest in project building, as has been reported Advertisement Manager: elsewhere in the hobbyist press, we are actually finding a greater demand for some PETER J, MEW, Frinton (01255) 861161 p.c.b.s and project software, etc. than has been the case in the last few years. We have Advertisement Copy Controller; also had to extend our web download quota recently because we have been exceeding PETER SHERIDAN, Wimborne (01202) 882299 the limit by more than fifty per cent for the last few weeks. READERS' ENQUIRIES You just need to look at the Chat Zone on our web site to realise how active EPE E-mail: [email protected] readers are. By the way, if you want to contact us with queries etc. please E-mail us, We are unable to offer any advice on the use, don't just post a query to Chat Zone as, whilst we keep an eye on what is going on purchase, repair or modification of com- and chip in occasionally with pointers, etc., this space is intended for readers to mercial equipment or the incorporation or modification of designs published in the contact each other and to help each other. It is very rewarding to see this happening magazine. We regret that we cannot provide and once again we have our Webmaster Alan to thank for getting it all off the ground, data or answer queries on articles or projects monitoring that everyone is playing by the rules and, of course, helping it along, that are more than five years old. Letters particularly in the early days, with help and directions etc. But it is your space for you requiring a personal reply must be accom- panied by a stamped self-addressed en- to enjoy and to help each other, there are already some "EPE regulars" in full flow, velope or a self-addressed envelope and so don't be afraid to join them with your queries or comments etc. It has proved to be international reply coupons. Due to the cost a lively forum. we cannot reply to overseas queries by Fax. All reasonable precautions are taken to ensure that the advice and data given to WORLD LEADER? readers is reliable. We cannot, however, We expect another boost to all this web interest now that we have EPE Online. guarantee it and we cannot accept legal Incidentally, as far as we can tell, we are the first magazine anywhere to be selling a responsibility for it. web version of the printed magazine. COMPONENT SUPPLIES We feel that it is quite an achievement for a relatively small UK hobbyist publica- We do not supply electronic components or tion to have beaten every other magazine in the world and achieved what has been kits for building the projects featured, these can be supplied by advertisers (see Shoptatk). talked about for some time. We have Maxfield and Montrose in the USA to thank for We advise readers to check that all parts are the World beating software that has allowed us to do this. still available before commencing any project in a back-dated issue. ADVERTISEMENTS E-mail: [email protected] Although the proprietors and staff of EVERYDAY PRACTICAL ELECTRONICS take reasonable precautions to protect the inter- AVAILABILITY SUBSCRIPTIONS ests of readers by ensuring as far as Copies of EPE are available on subscription anywhere Annual subscriptions for delivery direct to any ad- practicable that advertisements are bona fide, in the world (see right), from all UK newsagents dress in the UK; £26.50. Overseas: £32.50 standard the magazine and its Publishers cannot give (distributed by Seymour) and from the following air service, £50 express airmail. Cheques or bank any undertakings in respect of statements or UK electronic component retailers: Maplin - all drafts (in £ sterling only) payable to Everyday Practi- claims made by advertisers, whether these stores throughout the UK (and in S. Africa); Green- cal Electronics and sent to EPE Subscriptions Dept., advertisements are printed as part of the weld Electronics: Omni Electronics. EPE can also be Allen House, East Borough, Wimborne, Dorset BH21 magazine, or in inserts. purchased from retail magazine outlets around the 1PR Tel: 01202 881749. Fax: 01202 841692. E-mail; The Publishers regret that under no cir- world. An on-line version can be purchased from [email protected]. Subscriptions start cumstances will the magazine accept liability www.epemag.com with the next available issue. We accept MasterCard for non-receipt of goods ordered, or for late or Visa. (For past issues see the Back Issues page.) delivery, or for faults in manufacture. Legal BINDERS remedies are available in respect of some of these circumstances, and readers who have Binders to hold one volume (12 issues) are avail- complaints should first address them to the RONICS able from the above address. These are finished in blue p.v.c., printed with the magazine logo in gold advertiser. WORLD on the spine. Price £5.95 plus £3,50 post and pack- TRANSMITTERS/BUGS/TELEPHONE EXCLUSIVE ing (for overseas readers the postage is £6.00 to EQUIPMENT mBkSStm ^ everywhere except Australia and Papua New Guinea nwrOMMptMn awotc MfWm We advise readers that certain items of radio which cost £10.50). Normally sent within seven days transmitting and telephone equipment which but please allow 28 days for delivery - more for may be advertised in our pages cannot be overseas orders. FREE CO-ROM legally used in the UK. Readers should check Payment in £ sterling only please. Visa and Master- the law before buying any transmitting or Card accepted, minimum credit card order £5. Send, telephone equipment as a fine, confiscation of ■41 fax or phone your card number and card expiry date equipment and/or imprisonment can result with your name, address etc. Or order on our secure from illegal use or ownership. The laws vary server via our web site. Overseas customers - your from country to country; overseas readers credit card will be charged by the card provider in should check local laws. HicowiamomaKmaiEomMr your local currency at the existing exchange rate. Everyday Practical Electronics, December 1998 847 EE196 135 Hunter Street, Burton-on-Trent, Staffs. DEM 2ST Tel 01283 565435 Fax 546932 MAGENTA E-mail: [email protected] Homepage: http://ourworld.compuserve.com/homepages/Magenta.Electronics ELECTRONICS LTD All Prices include V.A.T. Add £3.00 per order p&p. £6.99 next day MAIL ORDER ONLY • CALLERS BY APPOINTMENT 1 " EPE MICROCONTROLLER PIC PIPE DESCALER | SPACEWRITER ■ An innovative and exciting Rl. TREASURE HUNTER • SIMPLE TO BUILD • SWEPT | project. Wave the wand through The latest MAGENTA DESIGN - highly • HIGH POWER OUTPUT FREQUENCY the air and your message appears. stable & sensitive - with MC control • AUDIO & VISUAL MONITORING I Programmable to hold any message ■ up to 16 digits long. Comes pre-loaded «£ of all timing functions and advanced An affordable circuit which sweeps ■ with "MERRY XMAS". Kit includes ^ pulse separation techniques. the incoming water supply with | PCB, all components & tube plus variable frequency electromagnetic PICDCSCALE* WATER . instructions for message loading. • New circuit design 1994 signals. May reduce scale formation, • High stability dissolve existing scale and improve Jj Everyday Practical Electronics, December 1998 849 Constructional Project '• r EPE MIND D n KLER ANDY FUND Part One not especially cheap and simple to build this Seven mind-bending, built-in project represents a huge improvement over earlier designs and is much easier to progrems to soothe your stste get working, since most of the complex functions are handled by the PIC. of mind. Relax with the power CIRCUIT DETAILS of a RiC entrainment machine. A broad outline of the EPE Mind PlCkler project's operation is shown in the block diagram of Fig.I. Program and Regular readers of EPE will TAKE YOUR PIC operating time selections are communi- probably be aware of the author's It seemed natural therefore, that follow- cated to the PIC microcontroller through enthusiasm for the design of "Mind ing assimilation of the excellent EPE PIC three inputs and acknowledged by beeps Machines", as several of these have been Tutorial series (March, April and May '98 from a directly driven piezo transducer. published in previous issues. Although issues and now available on CD-ROM) the Following this a 400Hz squarewave signal effective, the designs presented in the past author's first PIC-based design should be a is produced and a variable control volt- have been fairly complex to construct new Mind Machine, and this project is the age is created with seven binary outputs which may have discouraged some result. At around half the size and weight applied to an R-2R network. enthusiasts who would otherwise have of the 1996 design, it is the first capable of liked to build one of these devices. operating from a single PP3 battery. With WARNING NOTICE The main problem has been the method push-button selection of seven built-in pro- Photic stimulation at Alpha fre- of providing a "program" of output fre- grams and operating times it is also ex- quencies can cause seizures in quencies over an adjustable period. The tremely easy to use, the only other con- persons suffering from Epilepsy. For most recent version, in the March '96 to this reason such people MUST NOT trols being two knobs for Volume and try this project. April '96 issues, was user-programmable Brilliance and a Phase switch. A user who is not a known by means of sixteen variable resistors and, Although the programs are not user- epileptic, but when using the EPE whilst effective, it was by no means cheap changeable constructors wishing to try out Mind PlCkler begins to experience or simple to construct. their own programs can do so by re- an odd smell, sound or other With the arrival of the PIC unexplained effects, should TURN programming the PIC, since the seven IT OFF IMMEDIATELY and seek microcontroller chip this situation has session programs are just strings of numbers professional medical advice. changed quite dramatically. PICs are contained in a table (details next month) in Because of the above possibility, ideally suited to such control tasks and can the main program. It is not even necessary the EPE Mind PlCkler should not be result in much simpler circuits, since much to be completely conversant with PIC used while on your own. of the work is carried out by the software. YOU MUST TREAT THIS UNIT assembly language to do this. Although still WITH DUE RESPECT ELECTRONIC SWITCH BRILLIANCE CONTROL EXOR PULSE CURRENT COMBINER SHAPING DRIVER PULSE GENERATOR PROGRAMMING SWITCHES AND WIDTH 380Hz TO CIRCUIT CONTROL 398H2 f1 CONTROL|VOLUME \ MICRO- INPUT CONTROLLER R 2R NETWORK CONTROL VOLTAGE INTEGRATORS AND AMPLIFIER ^rsf^ » PIEZO SPEAKER HEADPHONES INTEGRATORS AND AMPLIFIER -(f'b- Fig. 1. Simplified block schematic diagram for the EPE Mind PlCkler. 850 Everyday Practical Electronics, December 1998 I The PIC's clock is tapped to drive a div- ider, which in turn triggers a pulse gener- ator which blocks the clock to the divider through an electronic switch. The blocking period is voltage controlled by the R-2R net- work output so, effectively, the second fre- quency is controlled by the PIC. The two outputs are combined with an EXOR circuit to extract their difference frequency which is processed for driv- ing l.e.d.s in the glasses. Each output also passes through two integrators which convert them into relatively pure audio \ sinewaves for driving the headphones. The full circuit diagram for the EPE Mind PICkler is shown in Fig.2. The seven push-button switches S! to S7 are used to select one of the seven programs, followed by one of seven session times. So that these selections can be passed to the PIC, IC1. using only three connec- The first of these is generated directly stand the action of this part of the circuit, it tions some simple diode and resistor logic by the PIC, using an interrupt routine to should first be assumed that Q12 (IC4 pin converts them to their binary equivalents, generate a 400Hz signal from port A bit 0 I) has been in the low state for some time which are applied to port A bits 2, 3 and 4 (ICI pin 17) whilst the main program is (relatively speaking!). Q12 is the output (ICI pins 1, 2 and 3). A third press of any running. The second is obtained from divi- preceding Ql 3 so it changes state twice for button then sets the program running for sion of the PIC's oscillator signal taken each change of Q13. the selected time. from "osc out" pin 15 and passed through •The low output from Q12 is applied to At any point during operation pressing the gates of IC2 to divider 1C4 (at clock an input of IC2c, pin 13. so the output of Reset switch S8 applies a brief reset pulse input), which reduces it to about 4(X)Hz. this is high. Applied to an input of IC2d to take the program back to the start where Port B bit 7, at ICI pin 13. is used to this allows the clock signal at the other it waits for fresh input. Power-up and block the input to 1C4 until the main pro- input to pass to IC4. all button presses are announced by brief gram starts. Whilst it is high, IC2a out- Meanwhile, capacitor C6 will have dis- "beeps" from the piezo transducer WD1, put (pin 6) is low, so the clock frequency charged through resistor R21, so the output driven directly by port A bit 1. does not appear at the output of lC2b. Fre- of comparator IC3 (pin 6) is high, and this The internal oscillator frequency of quency variation is achieved by blocking is applied to the other input of lC2c, pin ICI is set by crystal XI to 3-2768MHz, the clock signal briefly during each half- 12. When QI2 switches to the high stale. which gives a convenient internal clock cycle of the output from QI3 of IC4, this lC2c initially has two high inputs so the frequency for other timings required by time through IC2d. output goes low, blocking the clock signal the circuit. Two audio frequencies are through IC2d. needed, one fixed and the other differing VOLTAGE CONTROL However, capacitor C6 now commences from it by the programmed brainwave The period for which the clock is charging through R21, increasing the volt- frequency. blocked is voltage-controlled. To under- age at pin 2 of IC3. When it exceeds the BRAINWAVES They are also relatively difficult to use, since good, noise-free electrical contact must be made with the head. This usually involves silver electrodes and messy gels. The existence of electrical activity at various frequencies in the human brain was discovered many years ago, almost Stimulation as soon as the first electronic system capable of amplifying Because of these disadvantages they have largely been re- it became available The first regular waveform recorded, be- placed with devices intended to encourage production of the cause of its high amplitude, was named Alpha with a frequency desired brain electrical activity. By far the most effective way spectrum between of 8Hz and 14Hz. Subsequently other fre- of doing this is through "visual stimulation" by flashing lights quencies have been observed and are broadly classified into before the user's eyes at the intended frequency. Delta (0-5Hz to 4Hz), Theta (4Hz to 8Hz) and Beta (14Hz to The next most popular method is "binaural sound". At its 20Hz and above). simplest this consists of two audio tones having a frequency During the sixties experiments were carried out with a master difference equal to the desired brain electrical activity. Played of Zen meditation, where it was discovered that during deep through loudspeakers these would produce the familiar "beat meditation very high levels of Alpha activity were generated. note" effect, but in this application they are played separately, This led to further experiments in which feedback was used one to each ear, through headphones. The user's brain "syn- for training subjects to generate this kind of activity at will. thesises" the beat note internally and this is supposed to en- The intention was to reach states similar to those of advanced courage the desired brain activity. meditation, which normally requires many years of dedicated This is the method used by the EPE Mind PICkler in conjunc- training. Thus was born the technique known as EEG (electro- tion with flashing l.e.d.s and there is no doubt about the effec- encephalograph) biofeedback. tiveness of the two stimuli when combined in this way. The sound has a pleasant "bell-like" quality. It does have to consist AH in the Mind of fairly pure sinewaves as any noise or distortion is subjectively The science has advanced a long way since those early days far more intrusive than in most other audio applications. and the states associated with the other frequencies are now Other methods of inducing brain activity at specific fre- well understood. The low frequencies of Delta are associated quencies include magnetic fields (see the EPE Mood Changer- mainly with deep sleep (and young babies) and so have little June '98 issue) and the passing of tiny electrical currents practical application, except perhaps for insomniacs. Theta on through the head. You're not going to see a design for this last the other hand has been linked with intense creativity and so is method in EPE, though believe it or not, a couple of instruments of interest to many people wishing to generate artistic inspira- using this method are actually on sale in the USA. tion and innovative solutions to problems. Beta is predominant It is now generally accepted that the states experienced by in normal waking consciousness. users of this type of equipment are different" from those attained The original type of biofeedback device is not so common in advanced meditation, though they may form a good starting nowadays. They are difficult to build since they have to detect point for those wishing to pursue deeper spiritual growth. How- low frequency signals with an amplitude of a few microvolts, ever it is easy to reach states of deep relaxation, which in turn which generally have to be separated from several volts of may help in the control of stress. For this, and simply for recrea- induced "hum" caused by nearby household mains wiring. tional use, the EPE Mind PICkler is a very useful tool. Everyday Practical Electronics, December 1998 851 voltage at pin 3 ICS's output goes low, on the first and more on the second as the causing the output of IC2c to return to the end of the period approaches. The result high state and allow the clock to pass is that the voltage appears to change through IC2d again. smoothly through each step. The output is 14 +VE When Q12 returns to the low state this reduced to a maximum of just under half is immediately applied to IC2c to maintain the supply voltage by resistor R20 and 13 its high output and C6 commences dis- smoothed by capacitor C5. charging through R21, ready for the next Although this is the same procedure 3 operation. The period for which the clock used in the last Mind Machine, there are cycles are blocked depends on the voltage almost twice as many values in each pro- applied to the non-inverting input of IC3, gram and many more steps between them so a small voltage-controlled drop in the so the control action is much smoother. 10 output frequency from IC4 is obtained. With precise voltage regulation and crys- Note that 1C2 and IC4 are the tal frequency control the output is very 74HCxxxx high-speed versions of the accurate, and the shorter time constant CMOS 4093 and 4060 devices. Standard needed for smoothing the output makes for types are close to their operating frequency a much improved settling time when the 0V 7 Z7 limit at nearly 4MHz, and cannot be program commences. guaranteed to work in this circuit. In The numerical values corresponding to 74HC132 addition the 74HC132 pinout (see Fig.3) control voltages and output frequencies, differs from that of the 4093. held within the PIC, take into account the Fig. 3. Internal and pinout details for the The control voltage is taken from an R- exponential nature of the charging time of high-speed 74HC132 i.e. 2R resistor network, R6 to R19, connected capacitor C6 and the output frequencies to seven outputs from port B of the PIC measured in the prototype were found to possible so conversion is carried out by which provides digital-to-analogue conver- be within 0-1 Hz of their intended values. two integrators in each signal path. sion of binary values on these pins. Each Taking the upper signal path, which program is divided into 30 periods, each of processes the fixed 400Hz tone, the first which starts with a value corresponding to INTEGRATED integrator is IC8a which converts the one voltage and ends with one correspond- OUTPUTS signal into a triangular waveform. The ing to the next. The two output signals initially have integration response is set by resistor R39 The PIC alternates rapidly between square waveforms. The audio outputs and capacitor C21. C20 and R42 are these two values, gradually dwelling less should be as close to pure sinewaves as necessary for the stage to operate at the correct d.c. working point and, though Derivation of Formula for Calculating PIC Program Values they do introduce a little distortion, this is not audible in the output. The basic frequency of the two audio tones is 400H2. One oscillator is fixed at this Following the Volume control, VR2a, a frequency, whilst the other is lowered by having its clock input stopped for a brief instant similar second integrator, lC9a, takes the each half cycle. The actual length of this instant is the time it takes for C6 to charge to the triangle-wave from IC8a and converts it same voltage as the control output from the R-2R network R6 to R20. The maximum output into a sinewave. It also provides sufficient from this is 2-48V (127/128 x 2-5V). It varies in steps of 2-5/128 or about 19-5mV. power to operate Walkman type head- phones. If the fixed audio tone is 400Hz, the variable one must be 400-f Hz, where f is the required frequency difference. The signal level should be kept reasonably high here for a good signal-to- The period t for this is q_ . The period of the basic 400Hz tone is 1/400 or 0-0025 sees. noise ratio, so the output is reduced to an 40 ( appropriate amplitude by series resistor R49 rather than by lowering the input. A So, the clock must be blocked tor ^ -0-0025 sees per cycle. small tendency to instability under some conditions was corrected by the addition of resistor R47 and capacitor C25. However, it is blocked twice per cycle, so the blocking period t is half this, The second signal path for processing or 0-5 _ - 0-00125 sees per cycle. the variable frequency output from IC4 is 400 f identical. The sound quality obtained from this circuit is greatly superior to that of the The control voltage V1 from the R-2R network is given by V = 2-5 x , where N is the earlier Mind Machine designs. decimal value of the binary state of the seven outputs from it. BRAINWAVES _1 As in the previous design the two The voltage V2 across C6 is given by V2 = 5 x (1 - e t ), where t is the time constant squarewave signals are also combined R21 xC6 through two XOR stages to extract the Hence the point where VI and V2 coincide is reached when 2-5 x N = 5 x (1 - e —Lt ) brainwave frequency (see separate panel) and provide phase switching, for flashing the l.e.d.s (mounted in the glasses) either which can be reduced to N = 256x(1 -e-^-) in phase with the audio signals or in opposite phase to them. The output from IC6b is an 800Hz train t, of course, is 82k x 1 n5, which works out at 0-000123 sees. of pulses of varying width which, when averaged through a simple C-R filter, ap- pear as a triangle wave. Resistor R24 I (TO ) -000125 ^ ■1 applies d.c. biasing to this so that when So, we end up with N = 256 x \ 1 - e passed through the Schmitt trigger stage ^ 0-000123 '/ built with lC6c the output pulses obtained are only about a quarter of the length of The "1" being subtracted to correct a small but constant error found in practical testing. each cycle. Finally, in case the user programs a very low frequency, CI7 and R28 limit the f maximum pulse width to prevent overload This formula can be reduced to N = 256 l-e"^^'^® (0-0984xf) jl _1 of the battery and output l.e.d.s. The brilliance of the two l.e.d.s in the which is slightly easier to use with calculators or spreadsheets. glasses is controlled by varying their current. A control voltage obtained from 852 Everyday Practical Electronics, December 1998 ri-n iHi- I •- CM X G_ X cr2 1 otj-I II §1 ID £ —W—II— ss CV c si ^ II Oj cm CC ° o O X t CC^?:p 08 O o —V^A- 55 ^ 2^ II §i c\i"D r>r- T S-W— II—aAA- P '5 So o - sig Ss8P Op ojOS r. ico si oS W -? " X3c\i r; h B —w- ss Ox5^8 X - OJ Si 03 ^2 'i I t, —W u ^ i u«? i?. -^ n - ? cc LI OS 6 Eg UJ CC -W J^VA— s ? p X CO — o t n oj Q- < 5 9§ X< F/g.2. Complete circuit diagram for the EPE Mind PICkler. Everyday Practical Electronics, December 1998 853 potentiometer VRI is used by op.amp This method results in a current which POWER NEEDS IC7a and transistor TR1 to generate a returns to negative supply, which is useful Power for most of the circuit is 5V sup- small current which is converted back to a when the audio signals are also relative to plied by the regulator ICS. This is a micro- voltage, this time referenced to the positive the negative supply and sockets for both power equivalent of the well-known 78L03 supply, by resistor R31. Readers may be are fitted to the same metal panel. Insu- device, featuring very low operating current interested to learn that the eye, like the ear, lated 3-5mm sockets are hard to find, and and drop-out voltage which makes it ideal has a logarithmic response to intensity, so for this reason the earlier design had to use for use with battery supplies. It is also more potentiometer VRI should be a log law 6mm types with adapters. accurate than the standard type. type. The voltage across resistor R31 is Transistor TR2 turns off the l.e.d.s when The output stages for both audio and used by IC7b, together with transistors switched on by IC6d, so the pulses from l.e.d. glasses are supplied directly from the TR3 and TR4, to generate a much larger IC6d are negative-going to generate the 9V battery supply, though the l.e.d. stage current for driving the l.e.d.s. output flashes. receives this through resistor R38. It also has a very large decoupling capacitor, CIS, to prevent a faint "popping" sound which otherwise results from the sudden drops in COMPONENTS supply voltage caused by l.e.d. operation at high brilliance. Resistors R1 to R3, R5 4k7 (4 off) R28 390k SOFTWARE R4, R27, R42, RSI 1M (4 off) R29 3k3 R6 to R13 20k (8 off) R31 1000 The software in the PIC. 1C1, starts by R14 to R20, R30, R33 to R36, R32 1k obtaining the user's choice of program and R40, R41, R44, R45, R48, R55 10k (18 off) R37 in session time from the Program Select R21 82k R38 2211 pushswilches, then waits until instructed to R22, R25, R39, R50 100k (4 off) R43, R52 56k (2 off) start running the program. Once started, it R23 12k R46, R53 470k (2 off) loads a pair of values from a table held in R24 39k R47, R54 1011 (2 off) the software and alternates rapidly between R26 47k R49, R56 4711 (2 off) them, placing each in turn on the first seven All 0-6W 1% metal film type bits of port B. Potentiometers It increases one output period and VR1 10k min. rotary carbon, log. decreases the other in 255 steps, so a VR2 10k dual min. rotary carbon, log. gradual, smooth transition from the first value to the second appears to take place. Capacitors Following this, it replaces the first value C1, C2 10p resin-coated ceramic (2 off) with the second, loads a new second value C3, C16, C21, C29 10n resin-coated ceramic (4 off) and repeats the process. C4, C7, C8, CIO, C11,C13, It does this with a total of 31 values, an CIS, C19, C20, C23, C25, initial one plus one for the end of each of C27, C31, C34 100n resin-coated ceramic (14 off) the 30 steps that comprise a program. When C5, C9, C14, C26, C35 10Op. radial elect. 16V (5 off) C6 1 nS polystyrene, 1 % the last value has been used, it goes to an C12 470^, radial elect. 16V "end" routine where it loops at 3-second C17, C22, C28, C30, C32 470n resin-coated ceramic (5 off) intervals, bleeping each time, until the user C18 4700)x radial elect. 16V switches off or resets it for the input of new C24, C33 4n7 resin-coated ceramic (2 off) settings. All the time the main program is running Semiconductors interrupts change the state of port A bit 0 at D1 to D9 1N4148 signal diode (9 off) a rate of 800 times a second to generate D10, D11 5mm hyper-bright red l.e.d. (for glasses) the 400Hz output. Servicing the interrupt (2 off) TR1, TR2, TR4 BC184L npn silicon transistor (3 off) routine takes only a few microseconds, a TR3 BC214L pop silicon transistor tiny fraction of the time spent running the IC1 PIC16C84 or PIC16F84, pre-programmed main program, so its effect on this is not microcontroller, see text apparent. IC2 72tHC132 quad Schmitt NAND gate IC3 3130 CMOS op.amp FLOWCHARTS 1C4 74HC4060 14-stage ripple counter A flow diagram of the main program is ICS LP2950 5V voltage regulator IC6 4070B CMOS quad EXOR gate shown in Fig.4. Following switch-on or IC7, ICS OP296 dual op.amp (2 off) See reset, the program sets up the ports for user IC9 OP279 dual op.amp input, output bleeps and blocking of the clock signal to the variable frequency TALK Miscellaneous Page output. It then waits for a button to be X1 3-2768MHz crystal pressed, and stores the resulting input value S1 to S7 sub-min. pushswitch, push-to-make, black in a register. Valid button presses and (7 off) releases are both verified by a 40ms S8 sub-min. pushswitch, push-to-make, red software debouncing routine. The same S9, S10 sub-min. double-pole slide switch (2 off) SKI 2-1 mm power socket, with break contact procedure is used to obtain the value for SK2 3-5mm screened mono chassis socket, with session time, stored in another register. matching jack plug for glasses The program then waits for a third button SK3 3-5mm screened stereo chassis socket for press, following which it sets up the ports headphones . for output as required and starts the inter- LSI wire-ended piezoelectric sounder rupt routine for generating the 400Hz fixed B1 9V battery (PB3 type), with clip-in holder frequency output. The first value is called Printed circuit board available from EPB PCS Service, code 214; plastic case, from the table and placed in the register size 18Qmm x 120mm x 40mm; 8-pin d.i.l. socket (4 off); 14-pin d.i.l. socket (2 off); 16-pin d.i.l. socket; 18-pin d.i.l. socket; 20mm dia. max. plastic knob (2 off); for the second value, this being because the headphones, Walkman type; glasses (see next month); multistrand connecting program then goes to a repeating sequence wire; solder pins; solder etc. where the value in the second value reg- ister is transferred to the first and a new value is read from the table and placed in Approx Cost excluding case, the second. The output routine is then called Guidance Only dm headphones & glasses to perform the apparent gradual transition between the two values. 854 Everyday Practical Electronics, December 1998 Mb, II it - ~*Ui «:« j 1 iBU Li iism r?o This sequence is repeated thirty times and each time the register holding the table value pointer is checked. When it reaches SET "RATIO 1" TO 255 I SET UP PORTS SET "RATIO 2" TO 1 31 the program exits this loop to the final SET "SCALE" TO 41 FOR USER INPUT routine, where it stops the interrupts, blocks GET PROGRAM I the clock signal to stop the variable oscil- SELECTION | lator output, and goes into an endless long COPY "TIME" INTO "TIM- GET SESSION loop, bleeping each time it goes around. TIME SELECTION I The flow routine for generating the COPY "SCALE" TO "SCL" WAIT FOR smooth transition between the two values is START COMMAND I shown in Fig.5. It starts by setting two COPY "FIRSVAL" TO PORT B START 400Hz "ratios", used for the dwell times of the COPY "RATIO 1" TO "RATIO- OUTPUT two values. It then goes into three nested ENABLE VARIABLE loops with two more sequential loops at the DECREMENT "RATIO" FREQUENCY OSCILLATOR | centre, using values derived from the user's I GET FIRST VALUE Time input and a Scale value which sets the "RATIO FROM TABLE I overall running time to the correct value. The first program value from the table YES PLACE IN COPY "SECVAL" TO PORT B "SECOND VALUE- is copied to port B, "Ratiol" is copied to REGISTER "Ratio", and the first inner loop provides a COPY "RATIO 2" TO "RATIO" delay proportional to "Ratio 1". Then the second value is copied to port B, "Ratio2'r table POINTER is copied to "Ratio", and the second inner -31? loop gives the delay for "Ralio2". TTiese two operations are carried out for "RATIO- I COPY "SECOND VALUE- the number of times given by "Scale" multi- YES REGISTER INTO "FIRST VALUE" REGISTER plied by "Time", so it can be seen that DECREMENT "SCL switching between the two values always GET NEXT VALUE FROM TABLE takes place at the same speed, just over "SCL"=0? 2kHz, regardless of the value of "Time". PLACE IN YES "SECOND VALUE- Following this, "Ratio2" is increased DECREMENT "TIM REGISTER by 1, " Ratio 1" is decreased by 1, and CALL OUTPUT the process is repeated. This happens until ROUTINE "Ratio 1" reaches zero, when control returns TIM = 0? to the main program to update the two values YES from the table. INCREMENT "RATIO 2 |^TOP400HzJONEj The use of 255 discrete steps for each pair I",,^l!OPVARlABr^,,,,Ml of values means that even at the slowest rate FREQUENCY OSCILLATORj of change, for a running time of 40 minutes, "RATIO 1" BEEP AT the output voltage appears to change at over 3-SECOND three steps per second, so a smooth change of YES INTERVALS output frequency is obtained. This covers the circuit and program F/g.4. Flow diagram for the main operation. Next month we conclude with the Fig.5. Program flow diagram for transi- program. construction and testing of the unit. tion between two values. Everyday Practical Electronics, December 1998 855 New Technology Ian Poole discovers that "test tube" takes on a new meaning for microelectronics, and that Update^HHoxygenisation extends chip performance. There are two ideas highlighted this estimated to be over 1000 atmospheres. stray capacitance from components in the month. The first is associated The ultimate idea was to enable minute device to the substrate. witn minute connections required within conductors to be manufactured that could As a result, figures for SOI devices typi- microelectronics circuits. The second be used in integrated circuit manufacture. cally show a 35 per cent improvement in new development relates to the perfor- performance. This is not only useful for mance that needs to be achieved by Electric Light r.f. applications but also to give the in- integrated circuits today. It has also been found that the creased speeds required by today's proces- nanotubes themselves act as conductors. sors and associated chips. Even Smaller In a phenomenon known as ballistic In addition to the higher speeds, the Miniaturisation in electronics is con- conductance, these minute tubes give SIMOX process as implemented by IBM tinuing at an ever-increasing rate. To very low values of resistance. It has also offers the possibility of better low power achieve this, one of the main areas for been shown that the heating effect caused devices. The reason for this is that the research is naturally that of achiev- by the current flow is much reduced upon performance of SIMOX devices degrades ing smaller feature sizes within the what would normally be expected. less with voltage than do conventional integrated circuits. New developments in Enormous current densities have been CMOS devices. In tests carried out using lithography and the like are all under seen, with values of IOMA/cm2 being SRAMs, SIMOX devices consumed less investigation. achieved. Had the current behaved in power for an equivalent access time. However, there are many other new the normal manner then this would have and interesting ideas that are equally im- heated the tubes to temperatures in excess Cosmic Success portant to the miniaturisation process. In of 10,000°K. the years to come they will make large Investigations show that the current is A final advantage is in the reliability of contributions to the increase in the level flowing in a different manner to that nor- memory devices. On occasions, cosmic of integration. mally experienced. In this case the cur- rays and background radioactivity can Some of these ideas may seem far rent is flowing through the nanotubes as cause data errors. It is found that the level removed from the core electronics busi- if it was light passing through an optical of these errors is reduced with devices ness, but this does not mean to say that waveguide. fabricated using SOI rather than conven- they will not affect it. In the past many These effects have only been noted in tional CMOS i.c.s. In fact, the process ideas that may have appeared to have no nanotubes that are less than 5p.ni in was first developed for devices to be used bearing on one area of technology have length. At greater lengths the ballis- in space. Here the levels of radiation had an enormous impact. tic conductance effect appears to be are higher, and the degrees of reliability In one area of research being under- destroyed by the scattering effect of the required are much greater. taken at the Georgia Institute of Tech- electrons. The process itself involves the use of nology, nanotubes are being investigated. Whilst the maximum allowable length very heavy doses of oxygen, followed by These tiny tubes are made from carbon of these nanotubes may limit their useful- annealing at high temperature until a thin and have inside diameters measuring less ness, there will be many applications oxide layer is formed. The overall result than ten nanometres! The investigations within microelectronics. In addition to this, of the process is to give a thin layer of being performed on these minute tubes further development may enable their N + + material separated from the sub- could ultimately have important applica- applications to be extended. Despite the strate by a thin oxide layer. tions in microelectronics where extremely problems, nanotubes should be another Development of the process has been small conductors and other structures are technique that enables i.e. designers to hailed a success because once the basic required. increase the levels of integration. SIMOX process has been completed the substrate can be processed in the normal way. As the generation of the insulating Test Tube Chips Silicon on Insulator layer takes place during the preparation Whilst the work is still in its early The idea of silicon on insulator (SOI) of the wafer itself, rather than during stages, the researchers have been able to chips has been known for many years. the fabrication of the components in the put materials into the tubes and manipu- However, they have not been as widely device, this can be undertaken off-line. In late them. By doing this they have been used as many would like. The problem has this way the fab lines are riot disturbed. A able to induce chemical reactions. This been in enabling them to be made in further advantage is that it can be added has opened up new ways of thinking commercial volumes. to existing products, by simply using about the structures and they can be Now researchers at IBM have succeeded wafers that have undergone the SIMOX thought of as extremely small test tubes. in developing a process that can be easily process. The first stage in producing conductors applied to a whole range of CMOS In view of the fact that this process can was to try to deposit a conductor on the processes. In fact, the process has been be incorporated into existing lines, the cost inside of the walls of the nanotube. To qualified for their 0-22pm CMOS process, of its introduction is much less than one achieve this both ends of the tube were and is being developed for their 0-15 pm needing a completely new line to be set opened. Silver nitrate (AgNC^) was al- technology. The new advance results from up. This will mean that the i.c.s fabricated lowed to fill the tube by capillary action. a process called separation by implanta- using the new process will soon reach the Then the silver nitrate was decomposed tion of oxygen (SIMOX). marketplace. so that it formed metallic silver. This was The advantage of SOI is that as the Also, the cost of the chips will be less achieved by heating the tubes with a device itself sits on an insulating layer its than those requiring a completely new beam from an electron microscope. high frequency performance is greatly im- process with all the vast sums of invest- Initially, the process only produced proved. This results from two main effects. ment to get them up and running. This is tiny silver beads in the tube because a One is known as the "body effect" where all good news for the end user who will be small pocket of gas separated each bead. the size of the substrate affects the perfor- able to see improved performance for little The gas was under extreme pressure, mance. The other is in the reduction of added cost. 856 Everyday Practical Electronics, December 1998 Simulation Circuit Capture PCB Autorouting CADCAM Imagine an electronics design system that lets you draw schematics onto the screen and then simulate them at the touch of a button. Now imagine pressing another button and seeing the schematic replaced with a PCB rats-nest. Pressing another button starts the autorouter, and finally you can click on File then Save As to create a complete set of CADCAM files. Too easy? We hope so. Quickroute has always been designed first and foremost to be easy to use. That's why simulation, circuit capture, PCB autorouting and CADCAM support are all integrated into one package, So that you only have to learn one package. But it doesn't end there. We have included a wide range of features in Quickroute to help you work effectively. For example our Gerber import facility lets you check your CADCAM files before sending them to your manufacturer. We have also introduced a major new PLUGIN module called the SymbolWizard that actually creates custom symbol designs for you. Simply select a template, specify pad and spacing properties and SymbolWizard creates the schematic and PCB symbols for you! If you would like to find out more about Quickroute, why not call us on FREEphone 0800 731 28 24, or visit our web site on www.quickroute.co.uk. Prices start at under £100 including UK P&P and VAT for a complete system. "modern, powerful and easy fo use" Elektor Electronics 97 FREEphone jSMH 0800 731 28 24 Int +44 161 476 0202 Fax 0161 476 0505 Web www.quickroute.co.uk TEP 30 DAY MONEY BACK GUARANTEE Copyright (c) 1998 Quickroute Systems Ltd Regent House Heaton Lane Stockport SK4 IBS UK Electronics Principles 5.0 If you are looking for an easy and enjoyable way of studying or improving your knowledge of electronics then this is the software for you. By Clive W. Humphris. E3 f ler.troiw.i F>r»r»c:»ples 5 HOC DC AC Pow« Semi-Cond Op-Araps Maths Logic Measure Micto PIC* Help J* PtC« HABDWAl S (fci S4 Bl. < k 0iag.aiB BISBI <* .FR!! : AMD PARA! It I, REFI'noRF, Se.ies PaiaBel Resiclots Q33 "One r OSCILLATORS Wren Budge Oscillatoi that I've found is Electronics Prlncip Natural resonate freqency 636 6198Hz Voltage Vm' j Freqency forced to 1kHz range of electronics — Pocitr-e fcecfcaci 3V H BINARY AfllT R1 C1 covered is very wide, from 1 simple atomic structure to 2.9 1M>f the workings of the latest -1 5915k Decimal A IkHz microcontrollers. Binary | Z1 •ZR'j ci •/ R2 ♦Xcl2 V Binary » 2.9636k I was very impressed ... it .... = RxXc2 ran smoothly and without '-R2 C2 = ■ R3 I R^Xc? problems on several IBM 1st Binary num =1.3426k ■Negatrye leesSjact,- PCs." ?rwi Binary nun Vm 333 8mV / i = ZUS K2 i / R4 Addition Resut cSk 'lOOnf y Tex Swann. Technical Carry dwpts = 7(WpA Projects Sub Editor. 1 V^-lxZZ Practical Wireless -SSftaW B1,C1 and R2,C3 'oirr. a.c. voltage divider neivvori magazine June 1998. Rfvjto. 3 Calculations T opic Notes. PtWng. Wien Bridge OscHafor, "3 il Topic Notes I Pwting. || IrpU 'A' ) EXCLUSIVE OR Gate Topic Notes IrpjfB' SJjjIwilVinUERi' RC low P/m Ac»«*»i F*ei Constructing lowtrequency passive fitters often requires the use of inductors which can have large values and therefore are both expensive and bulky The same low frequency cut-off points can be determined using active fillers, where 'Electn 'rirtciples s a wejl inductors are rarely used owing to their d c resistance The simple arcuit shown has a roll-off of -20dB per decade To achieve steeper slopes the and comprehensive circuits can b The formulaelOSClLLATORS; AsUble Mullivibraloi s also easy to install impedance P — determine the || bOLU? operation. H can be Peiiod IT « 0,7 * OOOOOb [> ORCUt Iru*e Electronics Principles 5.0 £99.95* multi-user Site Licence £495.95* Windows 3.1,3.11,NT,'95 & '98 Please state CD-ROM or disks. EFT Educational Software. Pump House, Lockram Lane, Witham, Essex. UK. CMS 2BJ. Tel/Fax: 01376 514008. [email protected] http://www.eptsoft.demon.co.uk *UK and EC countries add £2 per order for post & packing. VAT should be added to the total. Outside Europe £3.50 for air mail postage by return. Switch, Delta, Visa and Mastercard orders accepted - please give card number and expiry date. Cheques & Postal Orders should be made payable to EPT Educational software. |m% m% ■ A t ■ A M A A roumluD & the latest Everyda mnovanons Hews srr01 INTELLIGENT TV RECORDING Is video recording of TV programs soon to become obsolete? Barry Fox reports. At the recent Live 98 show at If the Anytime Box is set to playback Simon Turner has another concern, Earls Court, London, one of the while recording, the viewer can break which PC users will understand only many panel sessions - Storage, a off to answer the phone, and then con- too well. "It's easy to store. But you Revolution on the Horizon - gave a tinue to watch a few minutes behind or have to apply your brain to throw valuable snapshot of the future. Within fast forward to catch up. things away. Hard disks get full and two years set-top boxes will be using NDS has already worked out a then people throw them away". computer disk technology to store pro- strategy whereby programme viewing is IBM was showing some prototype grammes automatically so that viewers free only for those who are willing to hardware that is claimed to work on the can choose what they want to watch by watch the adverts. Anyone who fast- TV Anytime principle. But it was a content, without being shackled to the forwards through the ad breaks will parasite event, off the exhibition site. time they are broadcast. quite literally pay for it. IBM had no official presence at IBC. Panelists Abe Peled (NDS), Simon Parnall (BBC), Simon Turner (Philips Research) and Jean Francois Jezequel (Canal+ ) all agreed that the cost of hard disk picture storage is now falling CODE HOPPER so fast (by a factor of a thousand over the last ten years) that within two Most of you will be years it will be cost effective for a familiar with Microchip as set-top box to store many hours of the manufacturers of programmes. By the Year 2010, at least the renowfTed PIC 500 hours will be easy. The cost of microcontroller family. MPEG-2 encoder chips will be down You may be unaware, to $40 by next year, so the "TV Any- though, that they produce time" box will work with analogue TV, a variety of other too. interesting devices as "It's on our doorstep" says Par- nall. "You can't stop it" says Turner. well, including the 1 KEELOQ Code Hopping "You've got about 18 months. Set-top A boxes definitely will have storage in Decoder family. them." Their latest KEELOQ Even as they spoke, three US com- device has been panies - Replay Networks of Palo Alto, developed for highly TeleWorld of Sunnyvale and the Duck secure remote-keyless- Corporation of New York - were entry (RKE) and access promising consumer storage boxes for control applications. The this winter. The Replay, TiVo and Duck HCS515 offloads all devices will record around seven hours timing and processing intensive functions from the system microcontroller. of programming. They cost around The device provides a complete decoding solution, handling reception and $500 because they need a digital con- validation of codes and recognising new transmitters. It combines high security verter to work with analogue TV. and low cost to make it an ideal solution for applications such as automotive All-digital boxes will need no converter alarm systems and immobilisers, gate and garage door openers, burglar alarm and could be cheaper. systems and electronic door locks. For more information, contact Arizona Microchip Technology Ltd., Dept ANYTIME BOX ERE, Microchip House, 505 Eskdale Road, Winnersh Triangle, Wokingham, The TV Anytime box will work like Berks RG41 5TU. Tel: 0118 921 5858. Fax: 0118 921 5835. E-mail: tech a server, programmed by its own ex- [email protected]. Web: http://www.microchip.com. perience to record whatever the viewer wants to watch, for playback whenever the viewer wants to watch it. At first the server will be Precious, and be very MAN POWER? selective about what it records. For in- stance it can keep updating the news so A SAMPLE pack of T5V AA-size Ener- camera flashes, 18 more minutes play that the latest is always on tap. giser Advanced Formula batteries, plus a with a motorised toy, 23 more pictures By 2005, falling costs will let the box press release have been received. The on a digital camera and 54 more minutes be Adventurous. By 2010 it will have latter states that these new batteries of talk time with a cellular phone. become Promiscuous, recording more deliver unsurpassed performance in high- Worthy improvements, indeed, but we or less everything, and leaving the drain and standard devices, and that "no are puzzled by some statements on the viewer with the problem of deciding battery lasts longer". packaging that accompanied the bat- what to watch. We are told that, compared to Ener- teries: "(Alkaline 0% Hg, Cd, Pb) 100% "It's a paradigm shift from time- 'giser's 1997 formula, the latest batteries testosterone. Makes your device last based to content-based viewing" says (actually, they ought to be referred to longer". Testosterone? Presumably, they Peled. "A new non-linear generation is as "cells" - but who bothers?) mean have man power - an alternative to growing up". increased playing power of 61 more Viagra, perhaps? Everyday Practical Electronics, December 1998 859 Dixon's Freeserve Net Software RADIO Free Internet access sounds attractive, but are AMATEUR there hidden snags? Barry Fox outlines the evidence. AWARD Dixons wants to buy a foothold in HELP CAN COST THE Radio Communications Agency the online market hy radically 1998 Young Amateur of Year Award changing the world model for Users will then need skill or help to has been won by 17 year old Mark Internet access. The British chain of restore their original settings. They can Shepherd from Brighton. electronics stores is giving away seek free help online (www.freeserve.net/ Mark was presented with the first CD-ROMs which contain a version of support/) or pay £l a minute to call prize of £300 by the RA's Director of Internet Explorer 4 that connects Dixons Technical Helpline (0906 553 Spectrum services and he also received a PC to Dixons' Freeserve site 5600). a certificate signed by Peter Mandel- (www.freeserve.net), gives the user an The user must go to Control Panel, son, Secretary of State for Trade and E-mail name and then provides free Internet, Connection and Settings, then Industry. He has also been invited to unlimited access. In return each user My Computer, Dial Up Networking, tour the Agency's Radio Monitoring has to answer personal profile ques- and right-click for Properties, to restore Centre at Baldock, Herts. tions on age, income and interests original settings. Heavily involved with the organisa- which will help Dixons target online IE4 will only support one setting tion of the Amateur Radio Club at sales offers. as a default, so users must change his school (Brighton College), Mark Dixons already has an online shop these defaults every time they want has many interests based on Amateur site (www.dixons.co.uk) but visitors to switch access between MSN and Radio. Packet Radio is a particular can only access it after they have paid Freeserve. (Right-click on the IE4 icon, interest for him and he has spent a an Internet Service Provider around for Properties, Connection and Settings). great deal of time and effort develop- £12 a month in subscription fees. Access to MSN may still be "denied" ing as a SysOp (System Operator) and Launching Freeserve, Dixons' CE John because Freeserve uses a proxy server running a BBS (Bulletin Board Station). Clare says he "knows of no shops that to improve response times by caching The Amateur of the Year Award charge an entrance fee". popular pages on the Dixons server. is organised in conjunction with the By design or accident Freeserve The fix is to use View in IE4, Internet Radio Society of Great Britain (RSGB) may hijack a PC, so that it can Options, Connections and unclick the and aims to encourage young people no longer use another Internet Serv- Proxy Server tick which Freeserve has into amateur radio. ice Provider with IE4, such as the added. For more information, contact The Microsoft Network (www.msn.co.uk). Dixons will earn revenue by letting Radio Society of Great Britain, If a user starts but does not finish the other companies sell their online serv- Lambda House, Cranbourne Road, registration process, Freeserve blocks ices to Freeserve users. The Freeserve Potters Bar, Herts EN6 3JE. Tel: access to other ISPs until the process software will soon also be available for 01707 659015. has been re-started and completed. download from the same site. Dixons Freeserve then makes itself the default corporate web site (www.dixons-group- for IE4, ousting other ISPs such as plc.co.uk) gives up to date details. So far MSN. it is available in the UK only. VALVE INTELLIGENT METERS HERITAGE THROUGH Readout we have been discussing the value of electronics "heritage". We were thus interested to receive a press release from the Bradford Public Relations Group ("Mission: To Promote Bradford") about young Ed Ross and his valve c'iWSh AC2T collection. Ed probably has the largest collec- tion of radio and TV valves in the UK and says that his passion for the devices, which began several years ago, was sparked off by reading electronics magazines and also from his father's collection of vintage radios. Hailing from Shrewsbury, 18-year "r-ib old Ed has just begun a three-year Network Information Management LASCAR Electronics have announced the introduction of their new family of course at Bradford University. He has intelligent digital panel meters, the C100 Counter, ClIO Frequency Meter and at least 3000 valves, obtaining them by C120 Timer. scouring second-hand shops and surf- Designed around a 6+3 character alphanumeric starburst display, these new ing the Internet rec.audio.tubes news microcontroller-based instruments include six 10mm high digits for measurement group for information and contacts. readings, and a 3-character display for indicating engineering units. Through the Net link, Ed met fellow The front keypad provides access to function choices, and all set-ups, including enthusiast Dr Donald Klipstein, of a calibration, are done in software. The meters have five open-collector alarm magnetics research company just out- outputs and are able to communicate via built-in RS232 or RS485 ports. side Philadelphia, USA, who has his For more information contact Lascar Electronics Ltd., Dept EPF, Module own valve museum. Ed's name now House, Whiteparish, Salisbury, Wilts SP5 2SJ. Tel: 01794 884567. Fax: 01794 appears on a brass plaque in the 884616. museum, after he donated rare valves to Dr Klipstein. 860 Everyday Practical Electronics, December 1998 THE DVD DILEMMA The security of digital video disc movie releases is being severely threatened. Barry Fox reports. Hackers are making a mockery The same chip disables the Macrovision the warranty if they tamper with the of Regional Coding, and copy encoder by blocking the trigger pulses. circuitry. protection, the two features of So a European player can copy a North Dealers in the Far East are already DVD which the Hollywood studios American disc onto tape. doctoring Pioneer's players before sale. insist on as a condition for releasing "Thanx to Bevis and Danny for this Techtronics offers to modify players for movies on the new digital disc format. great work" says a new web site a service fee of £40, and is sell- Magazine adverts and a site on (www.twi.ch/~i7eberha/eng/codefree5- ing Panasonic players that have al- the Internet now offer a chip which 05eng.htm) which uses detailed colour ready been modified, at an all-in price enables European players to play North photographs to show how easy it is to of £400. Techtronics says its offices American discs, and make copies onto hijack the Regional Coding and Macro- near Peterborough are so "busy" with VHS tape. A hew web site offers free vision circuitry on Pioneer's full range modifications that it needs 48 hours to advice on hacking DVD. It reveals that of DVD players. turn players round. Japanese company Pioneer is now sell- Pioneer's factory in Japan has put ing players which dealers can easily three spare contacts in the circuit board Force of Destiny adjust so that they play discs from any inside each player. Engineers can use The British Videogram Association Region. these points for testing. But simply represents all the studios which are DVD was conceived as a single connecting two of them with a blob of releasing movies on DVD. Hacking was standard digital video disc, which cut solder lets anyone set the Regional raised at the BVA's recent Council through the existing barriers between Coding of the player to any country of meeting. Says Director General Lavinia Europe and Australia, which use the choice, by pressing keys on the remote Carey "The studios think that as they analogue PAL TV system, and the US control. Photographs on the web site release more titles in Europe, there will and Japan, which use NTSC. After the also show how to disable the Macrovi- be less incentive to bypass regional base standard or DVD was set, the sion encoder. "After this mod you will coding. They see what is happening to Hollywood studios saw that it under- be able to play all movies without copy-protection and no longer feel in mined their policy of staggered releas- Macrovision" promises the text. control of their own destiny." ing. They want to save costs on making Although the BVA cannot stop people cinema film prints by releasing films in Undesirables tampering with Regional Coding in play- the US well ahead of other countries, Privately, the hardware companies ers, and mail-ordering discs from the which means they must also stagger admit that they did not want Regional US, anyone who sells imported DVD video releasing. Coding because they would sell more movie discs in the UK contravenes the So the electronic companies reluc- players if consumers had a wider choice Video Recordings Act 1984. They risk tantly tacked Regional Coding onto the of discs. But they dare not be seen to two years in jail, and unlimited fines, for DVD standard. Players are coded, and support hacking. selling films that have not been classified so are discs. Each bit of a 6-bit code The UK's DVD Launch committee, by the British censors. represents one of six Regions. The US which promotes the new format, says in The Disney Studio refused to support is Region 1, Europe is Region 2 and carefully chosen words "We could not DVD until it felt confidence in Regional Australia Region 4. If the bits do not sanction any unauthorised change to the Coding and copy protection. Says a match, the player rejects the disc. system". spokesman for Buena Vista, the sub- All players also contain a Mac- This is deja vu for movie buffs. Ten sidiary company which releases Disney rovision encoder, which distorts the years ago Pioneer kick-started the titles ,on home video "That's a tricky synchronisation pulses in the analogue market for 30cm analogue Laser Discs question". No further comment was video signal which the player sends to a in Europe with a similar tactic. forthcoming. TV set or VCR. A TV set can cope with Pioneer's model 1450 could play North David Simmons, Macrovision's MD the pulses, a VCR cannot. The encoder American NTSC discs through a Europe, explains that in Europe, defeat- is switched on by a trigger signal which conventional European PAL TV set. ing copy-protection is a civil rather accompanies the Regional Code. This upset the Hollywood studios so criminal issue. In the UK it is covered badly that Pioneer never advertised the by the 1988 Copyright, Designs and European Views feature, or explained it in the instruc- Patents Act. "Although the Act does Although DVD is now officially on tion book. But the news spread like cover devices designed to defeat copy- sale in Europe, only a limited choice of wildfire, and for at least a year Pioneer's protection, the law was deficient. Com- discs is available and most are old titles. dealers had a waiting list for 1450s. panies that produce the copy protection European movie enthusiasts want ac- Pioneer admits it is aware of the systems cannot take action. Section 48-7 cess to the much wider selection of information on the Internet about its says it must be the copyright owner who new movies available in the US. Hack- DVD players, and warns that users acts. We have to resort to suing under ers modified early players by disabling may damage their machines and void patent law". its Regional Code control chip. The movie studios countered by releasing discs which will only play if the chip is intact. Now the hackers have found NEW HAM PACKET a foolproof solution. They modify the player so that the user can set the Regional Code to suit whatever disc is BANDS RADIO CLUB to be played. European company Techtronics THE Radio Communications Agency MAXPAK, the Midlands AX25 Packet (www.techtronics.com) has announced has announced the date for future Radio Users Group have con- Multimod, an off-the.-shelf multi- changes to the 10GHz amateur radio tacted us saying that they hold purpose chip which the company says band. From I February 1999 the monthly meetings. If you are its "whizz kid" has programmed to put frequency allocation for radio amateurs interested in more details, contact Regional Coding under control of the using the terrestrial service is 10.00GHz Edward Loach (G4ZXS) on 01902 player's existing remote control. The to 10.125GHz and 10.225GHz to 741877 (evenings) or via web site chip costs around £40 and solders onto 10.475GHz. The amateur satellite g4zxs(« gb7max.#28.gbr.eu. The Club the main circuit board inside the player. allocation will remain unchanged. is affiliated to the RSGB. Everyday Practical Electronics, December 1998 861 Constructional Project c t FADING C CHRISTMAS LIGHTS yr BART TREPAK Use a PIC to provide PROGRAM The project is based around a PIC sophisticated programs microcontroller which means that virtually any program can be written to vary the for your tree lights. intensity of the three channels of lighting over a period of time. One program has been written and is available free or can be Flashing lights for Christmas trees and This is not quite how the idea for this purchased already programmmed into the other festive ornaments have been with project was bom but it should help to PIC chip (see later for details). us ever since electric light bulbs re- avoid this scenario. The circuit to be However, EPE readers who have fol- placed candles as the primary means of light- described has been designed not to flash lowed the PIC Tutorial series (March to ing up a Christmas tree. The original ones the lights on and off but to gradually fade May "98 and now available on CD-ROM) used a special lamp which contained a bi- them up and down, providing a more will be able to write their own PIC pro- metalic strip which heated up and broke an soothing, relaxing display with no sudden grams and thus design their own light internal contact causing the whole chain to changes in brightness thus avoiding the display. go out. With the current now interrupted, the "disco effect". The PIC is used to vary the output to strip would cool down causing the contact to Although designed primarily for three channels of lighting, each controlled be closed, lighting up the chain again. Christmas tree lights, the circuit could also by a triac. The circuit for the Fading This system is still used in many find uses in exhibition work or at more Christmas Lights will be described later, cheaper light sets but with technology sedate gatherings (a lightshow at an after we have looked at the techniques being what it is, it was soon re- afternoon tea dance perhaps?) or even as employed to control the power to the placed by transistorised flashers and now background lighting at a disco. A lights. microprocessor controlled ones are avail- particularly effective display could be able which not only flash the lights but obtained by using three different coloured MICRO-DIMMING play a rather "tinny" selection of lights such as red. green and blue and The most common technique used to Christmas carols as well! project these onto a white wall to produce dim mains lights using a triac is called a constantly changing colour or rainbow "phase-control" because the trigger pulse FLASHY effect. for the triac which switches the light is Flashing lights can be very attractive and certainly add movement and interest to the display which is fine if you want to hang them in your window to impress the neighbours or people passing by. But, pic- ture the classic Christmas scene: You are sitting in a darkened room in your favourite armchair. In the hearth the log fire is blazing, the Christmas presents „ have been opened, the long lunch/dinner t ft is over and, with a glass of brandy in your hand, you are watching the Queen's speech which you recorded earlier. But you feel tense, a slight headache, nausea - and you haven't even taken a sip yet! Was it the turkey? No . . . the stuffing perhaps ... or the extra helping of mince pies . . . and then it hits you. It's those infernal tree lights flashing on and off with monotonous rfegularity or switching to some even more annoying chase pattern. What is needed is something more gentle, calming, to help you relax and get ready for Boxing Day and another chance to spend some more money at the sales! 862 applied at the same frequency as the mains under the sine wave for the period during but not in phase with it. Put simply, the which the triac is conducting) and, in P.'.MNS Fig.2a, it can clearly be seen that the trigger pulse is delayed with respect to the VOLTAGE mains waveform. increase in power (shaded area) caused by The triac, once triggered then continues advancing the triggering point around the to conduct until the current through it is 1 10 middle of a half-cycle from t4 to t3 is 0V • " much greater than the increase achieved by reduced to zero (which occurs at the end of ,NPUT each mains half-cycle) so that if the trigger .2.5V A / '\]A B THRESHOLD advancing it by the same amount from t2 pulse is applied early, near the beginning * VOLTAGE to tl near the beginning (or end) of the : half-cycle. of the half-cycle, then the triac will con- KU // I _ i ■ \\ RAILPIC SUPPLY duct for almost the whole time, giving full ■325V ' ' i " This means that if the triggering delay is TRUE ZERO increased (or decreased) by equal amounts brightness. While if it is delayed and only CROSSING applied near the end of each half-cycle, then over a period of time, the lamp brightness the triac will be off for most of the time, WAVEFORM will appear to change relatively slowly and resulting in a low lamp brightness. Varying AT PORT RA2 perhaps imperceptibly at first, then fast ZERO around the mid-range of the half-cycle the delay between these two extremes will CROSSING give varying levels of brightness. (INTERNAL and finally slowly again as maximum (or Conventional light dimmers use a SIGNAL minimum) brightness level is approached. capacitor and resistor to produce the delay To obtain a relatively linear variation in required and, by making the resistor Fig. 1. Zero crossing point asymmetry. brightness with time, a correction must variable, the amount of delay and hence Pulse A appears too early white B too therefore be applied. the brightness can be manually controlled. late. Greatly exaggerated for clarity. In this application we want the brightness APPROXIMATION to vary automatically and we do not want This is not strictly true because the input To obtain a perfect brightness versus to have to turn a potentiometer up and threshold (the voltage above which a logic trigger delay characteristic (Fig.2b) would down to achieve this. The conventional high and below which a logic low is read), probably require the use of a fairly exten- way to do this would be to make the delay which is around half the supply voltage in sive look-up table but experience shows voltage controlled and apply a low CMOS circuits (i.e. 2-5V with a 5V sup- that this is not really necessary and in frequency triangular or sine wave to the ply). does not coincide with the mains zero practice a simpler approach can be used. control input, which would cause the delay voltage. This has the effect of making and hence the brightness to increase and the positive zero crossing appear to occur decrease in sympathy. slightly earlier and the negative slightly A similar method could be used with a later than is the case as shown in Fig.l, (A) microcontroller but, being a digital device, which is greatly exaggerated for clarity. it is far easier to produce a delay digitally This can cause asymmetry in the delay rather than using voltage control. Delays between positive and negative half-cycles in microcontroller circuits are very easily and other more serious problems and one achieved simply by loading a counter with way around this would be to provide a a number and then counting down until ±2-5V supply for the microcontroller in- zero is reached. stead of a single-ended —5 volts. Note The delay obtained will then depend on that a negative supply is used in this the rate at which the counting occurs design because triacs are more sensitive to (which is normally fixed and depends negative triggering. BRIGHTNESS on the system clock) and the number A simpler solution, however, is to in- 100% originally loaded into the counter which troduce time delays into the program so ^ACTUAL can easily be varied by software. Thus if that the crossings occur at the correct time, - APPROXIMATION the system clock is adjusted to cause the thus ensuring that any subsequent delay IDEAL counter to be decremented every 40ps for will start at the same time with respect to v/ example, then by loading the counter with the true zero-crossing point. 250 (decimal), it will reach zero in 10ms, while if only 10 were loaded, the delay FADE AWAY DELAY (PHASE would be only 400p,s. We now have a zero-crossing detector 180 ANGLE) and a delay, albeit in software, so that all ZERO CROSSING we now need to do is to switch an output Fig.2. (a) Effect of changing trigger It is not enough, however, to simply port which will trigger the triac at the delay at different points in the hall- provide a variable delay because to precise point to give any brightness re- cycle and (b) lamp brightness versus achieve the same brightness in successive quired. To make the brightness ramp up trigger delay. half-cycles, the delay must cause the and down we must arrange for the num- trigger pulse to occur at the same time in ber which is loaded into the phase delay The first thing to notice is that the each half-cycle. So it must always start at counter at each zero crossing to increase beginning and end of every half-cycle con- the same time by being synchronised with and decrease periodically. This is done by tribute very little to the total power so that mains waveform. storing the number to be loaded in another if triggering is restricted to the mid range The best reference point to use is the counter which can be incremented over the very little of the brightness range of the point at which the half-cycle starts i.e. the period we want the brightness of the lamp lamp will be lost. There will be no notice- mains zero crossing point. There are many to decrease and then decremented over the able decrease in the maximum brightness zero crossing detector circuits available time period during which we want the which will be achieved, while at the lowest both in integrated circuit form and discrete brightness to increase. brightness levels, the lamp is hardly glow- designs but again it is simpler to use the This will, of course, cause the bright- ing and producing virtually no light so that microcontroller especially as this requires ness to change in steps but, provided we this portion can also be discarded. This only one resistor. make the steps small enough, the change immediately gives a large improvement in The mains waveform is fed to one of the in brightness level will appear smooth and the characteristic because this centre por- microcontroller inputs (port RA3 in this continuous. In practice, 32 levels, which tion of the brightness against trigger delay case) via a resistor which serves to limit corresponds to a 5-bit counter, would curve is more linear. the current to a safe value and the input probably be sufficient, but this design uses A further improvement can be obtained port is read. During the positive mains 7 bits and 120 levels. by altering the brightness faster at the half-cycle this will read high and during Unfortunately, the relationship between extremities of the brightness range, where the negative half-cycle it will read low so the lamp brightness and the phase delay is the brightness changes more slowly com- that the instants at which a low reading very non-linear. This is because the lamp pared with that at the centre, by software. changes to high or a high reading changes brightness depends on the power fed to the Thus if the number in the brightness reg- to low will be the zero crossing point. lamp (which is proportional to the area ister (which ranges between 0 and 120 Everyday Practical Electronics, December 1998 863 in this design) lies between say 40 and Table 1: Subroutine Functions 80, the rate of change is made half of NAME SUBROUTINE FUNCTION that which occurs when the number to be loaded into the phase delay counter is DIMR Dimming routine which decrements PHSCTR and produces trigger pulses when outside these limits. it is zero The brightness is therefore increased or PSET Sets new brightness level for each output by increasing or decreasing the decreased twice as fast at the beginning number in the brightness register and changing the direction of dimming as and the end of the half-cycle compared to required. The rate of change of brightness is also linearised by the LIN the rate of change which takes place subroutines which are called from this routine. when the brightness is varied around the ZRX Zero Crossing Subroutine switches off triac trigger outputs and reloads the mid-portion. Together, these techniques PHSCTRs from the respective brightness registers (BRGs) give a visually almost linear variation in INPUT Reads switches and alters the values stored in the NREGs which determine brightness. how often the BRG registers are altered UP AND DOWN DELAY Short delay used to ensure that trigger pulses cannot be produced until after the Each of the three channels has its own mains zero crossing brightness counter (BRG1, BRG2 and BRG3) and these are all varied at the same Each subroutine ends with a return are used to increase or decrease the speed time and by the same amount so that they instruction (RETLW) which ensures that at which the brightness changes. This is will all remain in step as the brightness is after it has been executed, the program done by reading these ports and if either is changed. All that is required to ensure that returns to the line after the one from which high (switch pressed) incrementing or each channel ramps up and down con- it was called and continues from this point. decrementing the number stored in the tinuously is to make sure that the channel The function of each subroutine is des- NREG registers. The range of values continues dimming until minimum bright- cribed in Table 1. which the NREGs are allowed to assume is ness is reached (by increasing the count in limited to prevent very slow or very fast the respective brightness register) and then USER CONTROLS ramps. increases the brightness (by decreasing The only input/output lines required for The switches are read in a subroutine the count) until maximum brightness is this unit are therefore RA3 for the mains called INPUT which is called once in reached. signal from which the zero crossing timing every cycle, but this would result in the The decision on whether to increase or is derived and three outputs RAO, RA1 and value in the NREGs changing so fast that decrease the count in each brightness reg- RA2 to trigger the three triacs. The only even a short touch of the switch would ister is taken after examining another reg- controls provided are two pushswitches cause the contents of the register to change ister called, for want of a better title, connected to ports RBO and RBI which from minimum to maximum, allowing vir- the Dimming Direction Register (DMDR). tually no control other than fast and slow. Only the first three bits of this are used (A) To slow things down a bit, the subroutine (one for each channel) with a set bit in- includes a counter which only allows the dicating that the brightness of the cor- SET UP REGISTERS value of NREG to change once every 20 responding channel is to increase and a cycles. zero meaning a decrease. | SET UP I/O PORTS | These bits are then toggled when the OVERVIEW L—BEGIN brightness count reaches a maximum or a 1 DIMR 1 To summarise therefore, the brightness minimum, which ensures that the bright- of a lamp can be controlled by the contents ness begins to fall as soon as the maximum IS A3 LOW? of the respective BRG register, while the is reached and rise after the minimum •t- speed and direction of the ramp is deter- has been reached. Loading the brightness PSET mined by the contents of the respective and DMDR registers with suitable initial NREG and bit in the DMDR respectively. values then ensures the correct relative Z R X Since all of these registers are separate, brightness of the respective channels,as each channel can be varied independently they are faded. INPUT to produce any kind of display required. Thus, by leaving the bits in the DMDR SPEED JELAY register cleared, for example, and reload- The speed at which the brightness ramps ing the brightness register with the max- up and down is determined by how often DIM R imum value each time the minimum is the brightness registers are incremented or reached, a "sawtooth" brightness pattern decremented. This is done with the aid of will result with the channel fading down to another counter, or rather counters as there IS A3 MIGHT minimum brightness at a rale determined by are again three of these, one for each chan- -r: the contents of its respective NREG reg- nel, which are called NCTR1. NCTR2 and PSET ister, and then switching on to full bright- NCTR3. ness to repeat the process again. Similarly, These counters are loaded with a num- / F ■ by leaving the DMDR bit set the output ber (held in another set of registers called would increase in brightness. One output NREG1 to NREG3) and count off a num- DELAY could also be made to dim while the others ber of mains cycles before changing the increased in brightness at different rates. value in the brightness registers in the di- Note that once the output brightness rection determined by the DMDR register. reaches maximum, if the DMDR bit Here again, a larger number in the NREG DIG remains set, the output will stay at this will mean that zero in the corresponding brightness and would only change if either ^ IS ^ :-S NCTR will be reached after a larger num- PHSCTR=0 ■ the contents of the BRG register were ber of mains cycles resulting in a slower altered or the corresponding bit in the is NO ramp and vice versa. TAMPON DMDR was cleared. The same is of course A simplified flowchart for the program true for outputs that have reached mini- DECREMENT ■ ^ TRIGGER is shown in Fig.3a and consists of the main PHSCTR I VES TRIAC mum brightness. program which detects the zero crossing It is also possible to make outputs and a number of subroutines- which are remain at some intermediate brightness called as they are required. Each sub- RETURN level by switching the corresponding routine performs a single function such as DMDR bit high and low each time the decrementing a counter and triggering the BRG register is altered. This will in effect triac if required as shown in Fig.3b, the Fig. 3. (a) Main program flowchart and cause the output to ramp up and down by simplified flowchart for the dimming sub- (b) simplified dimming subroutine flow- an amount so small as to be hardly routine. chart. noticeable as a change in brightness. 864 Everyday Practical Electronics. December 1998 Alternatively, the program could be written in such a way that the contents of the BRG register are not altered when the COMPONENTS brightness is to remain at one level. Using these techniques enables the brightness of Resistors See TR1 toTR3 2N3903 npn transistor one or more channels to be "frozen" if R1 470n 0-5W (3 off) required while others continue to change at R2, RIO CSR1 to R11 2M2 (3 off) TALK CSR3 C206D triac (3 off) different rates and in different ways. 4k7 Page IC1 PIC16C54N programmed If there are many settings or patterns R4 to R6 2k2 (3 off) microcontroller - see programmed, then a larger number of R7 to R9 220n (3 off) Shoptalk switches will be required to select them RN 10k s.i.l. resistor network and, in this case, port B would need to be Miscellaneous reconfigured to drive/read a keyboard and Potentiometer LI to L3 4mH 100W, 240V open the INPUT subroutine re-written to do this. VR1 10k horizontal skeleton toroidal choke (3 off) Perhaps the simplest way of implementing preset FS1 2A fuse and panel mounting mains other lighting patterns would be to define a fuseholder register which would store the number of Capacitors C1 470n Class X, 250V a.c. S1, S2 s.p.n.o. pushswitch 250V the key which was last pressed. C2 470^ elect. 16V a.c. with plastic body - The other patterns would be written as 22p ceramic see text (2 off) subroutines similar to the PSET subroutine C4 to C6 10n Class X, 250V a.c. Printed circuit board available from the and these could be called from the main (3 off) EPE PCS Service, code 215; fully insu- program depending on which number was lated plastic case approx. 130mm x 65mm stored in the register. This is not difficult Semiconductors x 43mm; plastic p.c.b. mounting posts (4 to do but it is beyond the scope of this D1 4V7 500mW Zener diode off); p.c.b. mounting terminal blocks 2-way article. D2 1N4148 silicon diode (4 off); strain relief grommets (4 off); mains D3 to D5 red l.e.d. (3 off) cable; interconnecting wire; solder etc. CIRCUIT DETAILS Having discussed the software, it is time to examine the hardware required to do Approx Cost this. The full circuit diagram for the Guidance Only Fading Christmas Lights is given in Fig.4. excluding case & lights As with most microcontroller projects the circuit is unremarkable, consisting of the PICI6C54 chip itself plus the usual to drive three transistors (TRl to TR3) correctly rated for this application - see clock and input port pull-down resistors. which in turn switch the three triacs con- the components list. The frequency of the clock circuit is made trolling the lamps. Each transistor has an The circuit is powered directly from the variable by means of preset VRI to enable l.e.d, in its collector circuit which mimics mains (there being no good reason why the circuit to be set up (see later). the main lamp in brightness and these may it should be isolated from the supply) As mentioned, port RA3 is used to input be mounted on a front panel or left out if and a capacitor Cl (a Class X 25()V a.c. the mains waveform for the zero-crossing not required. capacitor) is used as a mains dropper in detector and it will be noted that two resis- Phase control unfortunately generates preference to a resistor. The a.c. voltage tors, R10 and R11, are used in series rather large amounts of radio interference (r.f.i.) developed across the Zener diode D1 is than one. This is because most resistors which must be suppressed if it is not to rectified by D2 and smoothed by C2 to are rated at 250 volts which is too low cause annoyance to nearby radio listeners provide a nominal 4V negative supply for for connecting directly across the mains, and this is the function of the chokes LI to the PIC. The current consumption of the which has a peak voltage of around 325V. L3 and capacitors C4 to C6 connected to circuit is quite low as the triacs are pulsed The other three lines of port A are used the triacs. These components MUST be rather than d.c. triggered. ■o N TB2 2 TB3-2 in.; LP1 LP2 IPS BRIGHTNESS C4T0C6 ^ ton CLASS X see lext 250V a.c. TB2/1 TB3/1 ib4 i Cl VR1 230V 470n 10k LI TO L3 L, MAINS R2 \ CLASS X SPEED SPEED 4mH 240V L2 I 2M2 250V a.c UP DOWN 100W '''12 Tlt2 mt2 4k7 CSR1 CSR2 CSR3 81 Ho 82 Ho C206D mil C206D C206D 4V7 FS1 OO—OO i m TB1/1 4 7011 I v DD MCLR OSC1/CLK IN RA3 -4-V\Ai RB0 RTCC RBI OSC2/CLK OUT . :'0'' -r-VNA-l RB2 TR1 -fAAA-i RB3 IC1 R4 2N3903 RB4 PIC16C54N 2K2 ^ TR2 RB5 RA2 RS ZN3809 -f-WM TR3 -pW-) HB6 R6 2N3903 RB7 RA1 2k2 RAO RN 22p 1N4148 8x 10k 1-4- Fig.4. Complete circuit diagram for the Fading Christmas Lights. It is most important that this circuit must be housed in a fully insulated plastic case. Everyda\ Practical Electronics, December 1998 865 CONSTRUCTION It is important to realise that all parts of this circuit are at or near mains poten- o o tial and under no circumstances should TO TO earthed equipment he connected to the S2 SI HZEIO® CSR1 p.c.h., nor should the unit he used whilst MTlfTT connected to the mains supply without •H Rn 03 MT2 being fully encased in a totally insulated plastic box - see later for details of this. The circuit is built on a small single- amaaaaaaA HZaZh CSR2 '0 MT,r sided printed circuit board (p.c.b.). The (Q) I^^tri r •0 component layout, together with full size wwWsWwwwW .U2 R copper foil master pattern, is shown in • / vRI •H 3 h* •0 Fig.5. This board is available from the TR2U b CSR3 ^ C6 » EPF PCB Service, code 215. • • 9 C .'T 1 •0 None of the components are unusual '.'T 2 •0 and should be available from most sup- a g pliers. Note that the PIC microcontroller e c TB1 •0 must be programmed for this application ct ♦-I m and for those who do not have the facilities O ® 6 O to program this device or prefer not to, a pre-programmed chip is available from the author - see Shoptalk for detail on this and on the availability of the software. o The pull-down resistors used in the 215 prototype were from an 8-way resistor network which is a single in-line package with 9 pins, one for each resistor and «]C a common. The common connection is marked by a dot on the body of this component and care should be taken to 8lOs ensure that this is inserted into the circuit m correctly with the dot adjacent to pin 5 of the i.e. 8l n (Z TAKE CARE The only other components worthy of note are the mains dropper capacitor C1 and the suppressor capacitors C4, C5 and C6 which must be rated at 250 volts a.c. s o Class X types, suitable for connection di- rectly across the mains supply. Do NOT be tempted to use an ordinary 250 volt polyester type as these are normally rated at d.c. and could break down causing ex- Fig. 5. printed circuit board topside component layout and full size underside tensive damage to the rest of the circuit. copper foil and master pattern for the Fading Christmas Lights. The triacs should also have a minimum voltage rating of 400 volts and have a low few pence. The mains connection and the screw terminals and strain relief grom- trigger current requirement (i.e. a sensitive connections to the lamps are made using mets used in the case. If other lighting gate) with a rating of 5mA being ideal. screw terminal blocks which are also arrangements are to be employed a Bulgin The C206D (which is a 400V device) is soldered onto the board. 8-way mains connector (of the type used in best as it also has a low latching current The off board components will, of many light chasers) could be used to make which is important when low power loads course, be panel mounted and connected to the connections. such as Christmas tree lights are to be the board with flying leads. If the circuit is The circuit may be mounted in any plas- used. to be used exclusively with Christmas tree tic box of suitable size, there being many This triac can be used to control up lights, these can be connected directly to on the market to choose from ranging from to 750 watts of lighting provided it is mounted on a heatsink. Without a heat- sink I00W would be more realistic, which should in any case be more than enough for most applications. Note that the tab of this device is not isolated so that a mica insulating kit will also be required if a heatsink is to be used. The chokes should also be suitably rated to carry the lamp current. CIRCUIT BOARD All the components except the two switches and the fuse are mounted on the p.c.b. and construction should follow nor- mal practice with the lowest profile com- ponents such as resistors and •diodes being • * • ♦ mounted first. It is also a good idea to fit an 18-pin d.i.l. socket for the ^ • microcontroller rather than soldering it directly to the p.c.b. This is a CMOS Early prototype of the printed circuit board. Some of the components, namely the device and although quite robust there is inductors and capacitors, have been repositioned and a mains rated terminal block no point in tempting fate for the sake of a included for the mains input lead. 866 Everyday Practical Electronics, December 1998 the plain functional to the more attractive. The choice is left to the individual. The circuit board should be mounted on plastic stand-off pillars (the self-adhesive ones are probably the easiest to use) and suitable holes should be drilled in the corners of the board for this. TESTING TIME Once construction is finished check that there are no solder splashes on the board which could short out adjacent tracks. Do not insert ICI yet. The circuit MUST be mounted in a fully enclosed plastic case and no metal part should pass through the case (except of course for the mains wiring which must also be insulated in the normal way). This means that switches SI and S2 MUST be plastic bodied types rated for mains insula- tion - see the components list. ON NO ACCOUNT SHOULD ANY OTHER CASE ARRANGEMENT BE USED FOR THIS PROJECT. If you are in any doubt about your ability to build 230V a.c. CHRISTMAS LIGHT CHAINS OR SPOTLIGHTS (tOOW MAXIMUM FROM r?Amn EACH OUTPUT) this mains project safely then consult a LP1 LP2 LP3 qualified electronics engineer. Remember this circuit operates at mains potential, do not use it whilst it is con- nected to the mains unless it is fully cased as described above. DO NOT EARTH ANY PART OF THIS CIRCUIT. TEST LAMP FULLY INSULATED It is a good idea to connect a lamp PLASTIC CASE of I00W-150W in series with the mains (S) o (S) o (S) Everyday Practical Electronics, December 1998 867 . ■ . L n 11 n o www. epern a Buy your magazine online. EPE, the first magazine in the world to be available to buy from the web. $3.95 per issue, $23.95 for a - year's subscription. TAKE A LOOK, A FREE ISSUE IS AVAILABLE Save money on printed copies - take out a subscription NEXT MONTH - CRACKING THE SOUND BARRIER! VOLUME COMPRESSOR Name EVERYDAY Address . I PRACTICAL ELECTRONICS Post code . 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WWW: htfp-J/waw.labcantar.coMk abcenten Fully interactive demo versions available for download from our WWW site. Call for educational, multi-user and dealer pricing - new dealers always wanted. E e c ironies Prices exclude VAT and delivery. All manufacturer's trademarks acknowledged. WIN A DIGITAL MULTIMETER The DMT-1010 is a SVj digit pocket- sized l.c.d. multimeter which measures John Becker addresses some a.c. and d.c. voltage, d.c. current and resistance. It can also test diodes and of the general points readers bipolar transistors. have raised. Have you anything Every month we will give a DMT-IOIO interesting to say? Digital Multimeter to the author of the □ rap us a line! best Readout letter. UNINSTALLING PhizzyB DEMO "Uninstall" utility that you use to remove the (b) It can leave all of the DLLs it loaded without Dear EPE, PhizzyB from your system. But wait, there's asking you I had a look at your free CD-ROM given more. .. (c) It can query you as to what you want to do away with the November '98 issue and decided In the past, when one created programs, about the DLLs to uninstall the PhizzyB demo - WHAT A those programs were often single humongous DISASTER - the uninstall program decided to "chunks" of code. These days one tends to In practice option (a) is almost never used, do its job with a sledge hammer instead of a make use of dynamic link library (DLL) and because you run into the problems that you ex- nutcracker removing important files (.DLL files) object code extension (OCX) files. Like most perienced. Options (b) and (c) are pretty much which my computer needed to run my most programmers, when we created the PhizzyB, we equally common. Option (b) has the advantage that important programmes - Lotus and Wordpro. I generated some PhizzyB-specific DLLs, and we inexperienced users aren't presented with questions think if I had had the programmer I would have also made use of some standard Windows that are too complex for them to handle, while strung him up. 95/98/NT operating system DLLs, plus some option (c) has the advantage that it gives more Please pass on my disgust to your friends in Visual Basic DLLs, and so forth. experienced users more control. Unfortunately, as America and let me know how I can get this When the setup.exe program runs, it checks to occurred in your case, the option we used - option B***** Bee out of my computer without mess- see what DLLs are on your system. We can (c) - does mean that less experienced users can run ing things up. usually assume that the operating system DLLs into problems. 1 had to re-install PhizzyB to re-establish are there, but we can't guarantee say the Visual As a general rule of thumb (and like many normality. Basic DLLs, and the only way the PhizzyB- users), if I am uninstalling any piece of software John Bird, via the Net specific DLLs would be there is if you pre- and am asked about whether I wish to remove a viously installed this little rascal. The end result DLL that I'm not sure about. I always choose to We forwarded John Bird's missive (missile?) is that the setup.exe file checks to see what leave it on my system. lo Our Friends in America - you've got and what you're missing, and then If you re-run the "Uninstall PhizzyBD" option, installs any absent components. you will see that at some stage during the installa- Dear Mr. Bird, On this basis you might assume that the tion it does start saying things like "xxxxx.DLL is It's Clive "Max" Maxfield here — one of the Uninstall program would know exactly what it a shared file, do you wish to remove it anyway?" creator's of the PhizzyB. With regard to your has to remove from the system, but life is a little Again, as a rule of thumb, if you aren't 100 per message that EPE forwarded to us, as follows: more complex than this. Suppose, for example, cent sure what you're doing, it's generally a good I'm very sorry to hear that you've been that you now decide to load a "super duper" idea to select the "NO" option in these cases. having problems, but 1 think you are being a graphics utility that you just purchased, and let's A little later you will be prompted as to whether little harsh towards us - especially with regard further assume that this utility uses one of the you wish to remove the PhizzyB's directories. In lo your desire to "string us up ". Let me same Visual Basic DLLs that the PhizzyB al- this case the Uninstall will prompt you for each of explain ... ready loaded onto your system. In this case, the the PhizzyB's directories in turn, and you can feel When someone creates a program like the setup.exe for your new graphics program will free to instruct it to delete these directories PhizzyB (and unless we're talking about an see that this DLL already exists and won't in their entirety. Once again, we could have organization like Microsoft), that person doesn't bother loading it - so now this DLL is being simply caused the Uninstall utility to automatically actually create their own installation program. used (shared) by two programs. remove these directories without prompting, but Thus, when we created the PhizzyB, we used a There are three ways for an Uninstall program more experienced users may wish to keep certain commercial tool (an "Install Shield") that takes to work: directories containing data files they've created, so all of our files and generates the "setup.exe" we decided that it was preferable to give people the program we placed on the CD. Furthermore, (a) It can remove all of the DLLs it loaded with- ability to control their own destiny. this program automatically generates the out asking you So you can uninstall the PhizzyBD as des- cribed above, or as a "quick and dirty" alternative, you can simply delete the C:\PhizzyBD directory and all of its contents. Note that this route will ★ LETTER OF THE MONTH * still leave the PhizzyBD and Uninstall PhizzyBD entries in your "Start -> Programs" menu. In order GLOBAL TUNING on a crystal set) when I receive an amateur to remove these entries, you'll need to use "Start Dear EPE, thousands of miles away on a radio made from -> Settings -> Taskbar" to bring up the Taskbar I was interested in Philip Miller Tate's and a few still obtainable discrete components and a Properties dialog, then select the "Start Menu" Harold Chamberlain's letters in Readout Sep- length of wire to a tree in the garden. tab, then the "Remove" button, and then select the tember '98. I am not going to pay £200 for a digital items you wish to remove. My interest is largely centred on radio. I radio. In my ignorance I suspect that all these Once again, I'm sorry that you've experienced am a "kitchen table" constructor, of Scot- will be is a front end digital-to-analogue con- these problems, and I hope that these notes have tish descent, and have, like Harold C, limited verter which 1 can make for very little. So I helped to resolve your questions. Hopefully funds. I have 20-odd home-made radios scat- would be obliged if EPE would publish a cir- you'll now agree that "stringing us up" is tered around the place, and if the cost is more cuit for a digital radio. Thank you! perhaps not as warranted as you first believed :-) than a fiver each, I think of another and cheaper Peter McBealh, Please feel free to E-mail me at way of making them. Morpeth, Northumberland http://maxmon.com if you have any other This restricts me in some ways, but Robert issues. Penfold showed me the way many years ago and Frankly, at present we believe that it would Clive "Max" Maxfield I was lucky because I bought Denco coils when not be possible lo build a digital radio from they were 50p each, and were still around. I have conventional' components any more cheaply B.A.E.C. SAVES MONEY! moved on to Toko coils and i.c.s, but the best than using the specialist chips designed for the Herbert Howard of the British Amateur Elec- radios I have, covering everything up to 30MHz, purpose. However, whilst the cost of such chips tronics Club also responded to Harold Chamber- are made from discrete transistors and Denco remains high, with the current emphasis on lain's letter in Readout September '98. To cut coils from circuits dated 1976/7. digital broadcasting in general, it seems likely short a rather lengthy story, Herbert contacted I have reception pins on a" world map in that the cost should eventually plummet. It Harold and told him that by joining the B.A .E.C. every country, and I don't think there is a would then be more realistic lo ask regular he could avoid high postage charges, and in better way to encourage the "re-appraisal of contributors or other readers to offer us a doing so easily save his subscription lo the Club. our heritage" than by making radios. The hairs circuit for possible publication. Harold has joined! on the back of my neck still prickle (as they However, if anyone knows of any low-cost So could you - contact,/. E. Davies. Secretary did when 1 received the first transmissions devices already on the market, tell us! B A.E.C.. 70 Ash Road. Cuddington. Northwich. Cheshire CW8 2PB. Everyday Practical Electronics, December 1998 871 COMPUTER FREE ZONE? MAINS SAFETY L OF A PROBLEM Dear ERE. Dear EPE. Dear EPE. I have taken PEIEE for 25 years, but feel that Two aspects of the Mains Socket Tester (Sept I have a problem with the Single or Dual you place too much emphasis on computers. If I '98) concern me. Tracking PSU of April '98. wanted a computer magazine I would buy one The first is the fact that there is no protection The trouble is with the tracking part of the quite specifically. The fact is that not only can I for this mains operated device. If there were a circuit and I find that all the voltage is across the not find stand-alone projects of a non-computer fault within the tester it would rely on the fuse or positive side (8-7V) and only I-2V/1-3V across or PIC nature in EPE, but cannot find this at all circuit breaker at the consumer unit to operate. the negative side when the output is set to 10V in any electronics magazine. This would be at least 30 amps rating and would on Single. Varying the voltage via VRI. I still I have nothing against computers in general result in considerable damage to the tester at a obtain the same 1-2V/1-3V across the negative and use them at work for teaching purposes, to time when it was being plugged in, with conse- side, with all the other voltage dropped across help people with teaming difficulties. The fact quent risk of injury to the operator. the positive side. stands, though, that I do not have a computer at A possible solution to this would be to build What might be the cause of the problem? home and am sure that the same applies to many the device in a separate case and connect it with Mark Sammons, readers. Surely there is room for a magazine a short length of cable and a I3A plug-top fitted Alvaston, Derby which avoids them? If you force-feed any crea- with a 1A fuse. Alternatively, consider using 5A ture on even the best food, it will lack the fuse-wire (in a PVC sleeve) to connect between The above is an extract from a much lengthier nutrients contained in all the other foods. the plug connection and the circuit board. letter from Mark in which he quoted all sorts of Every sincerity intended. My second concern is misleading indication other voltage readings as well. Adrian Hoare. of satisfactory earthing. Whilst the device will It seemed to us that the problem lay with the Morpeth. Northumberland give correct indication for a good Earth or no TR3/TR5 path and that the voltage across them Earth, it will give false re assurance for a poor was the sum of their base-emitter drop voltages The above is a precis of I he comments made Earth. If the resistance of the Earth conductor is (the said I-2VII-3V), suggesting that TR3 was in two letters from Adrian, to whom Editor Mike 1000 ohms, say, the device will still indicate a incorrectly inserted. replied directly. good Earth although such an Earth is of little use Speaking to Mark by phone, he assured us In a nutshell, computer related articles are as any fault current will be insufficient to operate that TR3 was inserted correctly according to amongst the most popular projects in recent the circuit fuse. the published layout diagram. Puzzlement at our years. The solution is to connect a resistor of, say, end! Then the penny dropped - was the correct We do publish a great many non-computer 22 kilohms 3 watts between Live and Earth. version of TR3 being used? The specified device projects, as a browse through the Annual Index This will check the integrity of the Earth con- is a BC2I2L (note the L suffix). It transpired in this issue will prove. We are an ' 'electronics'' ductor by passing a small current to Earth during that Mark had inadvertently purchased the ordi- magazine and we try to cover all aspects of the test. This current will allow the tester to nary BC2I2 (without the L suffix). electronics - a field which very heavily includes indicate correctly but should be low enough to Unfortunately, the two versions have different computers as well as the more "conventional" not operate any Earth leakage protection. pinouls and although physically Mark had circuit applications, which are loo numerous to John Fenton, his transistor aligned as published, the pins itemise. Garstang. Lanes were electrically in the wrong order. Problem However, we listen to what readers tell us detected and cured - reorientating the BC2I2 so and. as always, want you all to keep us informed We referred this letter to Bart Trepak. the that its pins were in the correct holes: not loo of your likes and dislikes. Adrian, your com- author, who replied: much contortion! ments are taken in the good faith in which they The moral of the story is that identically were intended. I have used an identical mains dropper cir- numbered transistors having an L suffix cannot cuit on many occasions in the past, including on be used in place of those without, unless they circuits which are and have been permanently PASCAL? have their legs reorientated. A better solution, of connected to the mains, and have never yet ex- course, is to ensure that you buy the L version Dear EPE, perienced any fault of the nature you describe. Having read EPE for a couple of years, I wish when it is called for. This is, of course, not proof that such a fault Whereas some transistors, such as the BCI08 to thank you for the help that you give me in could not occur and the obvious one is of the increasing my interest and knowledge in this for example, are available with suffixes of A. B. C capacitor breaking down. The capacitor speci- or none at all and all have the same pinoul nota- hobby. My favourite parts are Ingenuity Un- fied is designed and rated for such applications limited. New Technology Update and Interface. tion. those having L versions available do not. and a fault of this type is, therefore, unlikely. In the former case, the suffix indicates the A subject I would like to raise is that of the However, if it should occur, the capacitor is main programming language you use. Since I transistor's gain range, with the latter it indi- designed in such a way that the metalisation on cates the pinoul variant. Beware! am quite familiar with other languages (I am in the dielectric around the point where the break- my third year in the BSc IT course, specialising down has occurred will vaporise, thus restoring in Computer and Communications Engineering), the integrity of the capacitor. STATESIDE OK I find BASIC an old-fashioned and inefficient This self-healing characteristic is common to Dear EPE, programming language due to the fact that it is all capacitors rated for direct connection across Recently I became a subscriber to EPE after interpreted rather than compiled. the mains and would occur in a time much several years of spotty newsstand service (and My suggestion is to move to a higher program- shorter than it would take a normal fuse to blow. many requests for back issues). Over the ming language, proposing PASCAL. This is an Even if this were not the case, resistor R1 would course of those years, I have also subscribed easy to use language with a readable syntax. It is not last very long (being rated at only 0-25W) to several other electronics-related periodicals, also compiled and results in much faster code, and and would fail open circuit, therefore acting as a both in the UK and here in the USA, and PASCAL units are readily available to be used. fuse. have concluded that yours is the best overall Joseph A. Zammit, In general, any circuit can always be im- enthusiast/education publication. Balzan. Malta proved by considering what would happen if this 1 part-time teach/assist at a local technical or that component failed and fitting protection college and a local radio/electronics club. Other In fad. a number of programming languages components, but in the end the designer has to teachers, students and enthusiasts to whom 1 are used in our projects from lime to time: consider what is the likelihood of such a failure. have shown your magazine seem to agree with three variants of BASIC (GW-BASIC. Quick- There is, of course, nothing wrong with a this conclusion. I suspect this is in part due to BASIC and QBASIC), various forms of C "belt and braces" policy especially where mains your apparent close ties to various educational (occasionally), assembler for 8051 and family, voltages are concerned and those who feel that a institutions. assembler for 8086 and family, and. of course, "piece of string" is also called for can add a Your constructional projects (even the more assemblers TASM and MPASM for PICs. So far fused plug as you suggest, but my experience is advanced ones) seem to yield a high rate of as we recall, we have never been offered that unless a high speed fuse is fitted, the circuit, success upon completion, even by complete software written in PASCAL, and somehow if it is to fail, will fail with the components novices. I believe this is a result of a level of doubt that many readers are actually familiar blowing first and protecting the fuse. diligence/thoroughness-of-detail not exercised with it. Nor have / ever had working experience Your suggested modification for indicating a by similar publications. 1 find the level of your of it. Nonetheless, we would be interested to poor earth is interesting and although I have not tutorial material (Teach-in plus Lab Work) to be know what other readers feel about PASCAL - tried it, this would no doubt be a useful addi- exceptional, and the PIC Tutorial series is and I'll extend the question to include opinions tional feature. It should, however, be remem- fantastic - best I've ever seen! on C and its variants. bered that the circuit is not intended to provide Bob Schoonmaker. Also, how many of you have ac.cess to Visual a comprehensive test of the mains supply but Woodside, New York. Basic? Is it something that we should include in simply to indicate that the correct connections via the Net our repertoire? / bought it a while back, but had been made. As mentioned in the article, the have not yet delved into it. If enough of you circuit would not reveal an error in confusing the Thanks for your appreciative comments and know how to use VB and would like projects Neutral and Earth but this, like a high resistance your suggestions. We are alt convinced of the written for it, it would give me (and others, per- Earth (as opposed to a disconnected Earth), is a necessity to encourage education in electronics haps) an incentive to become familiar with it. much more unlikely fault. and to try to explain things in detail suited In Give us answers please! Bart Trepak various levels of reader experience. 872 Everyday Practical Electronics, December 1998 The Encyclopaedia hdata-net: of Electronic Circuits tJhether you are an Amateur or an Engineer, this encyclopaedia is an incredible mine of information and will help you to save hundreds of hours of search. The 10 CD-ROM set contains complete datasheets on over 180.000 circuits from 61 manufacturers which represents more than 300.000 pages of technical information in PDF format. The search engine helps you to find the datasheet of a specific circuit in seconds, compare several circuits at the same time and print or export the data. cso-mcAi PACA i rnsmi To receive the 10 CD set of Data-Net for only £39 (inc. 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Normally supplied within seven days of receipt of order. Circuit Surgery • Net Work - The Internet Send a copy of this form, or order by letter if you do not wish to cut your issue I M12/98 f • Chip Special - HT7630 PIR Controller. 874 Everyday Practical Electronics, December 1998 Constructional Project x HANDHELD FUNCTION . GENERATOR BRIAN ADK/NSON truly pocket-sized instrument, The second type of injector is a little more elegant, producing a sine wave with three switched ranges output instead with, perhaps, the added refinement of an output attenuator. To covering 50Hz to 20kHz. keep things simple the frequency is again usually fixed at (say) 1kHz. The sine wave might be derived from a IN DESIGNING this little project the aim Wien bridge, twin-T or phase-shift was to build a hand-held audio //V COMPARISON oscillator. Carefully designed all are generator with a few more features than Apart from a few specialised tests re- capable of giving a low distortion those normally found on the simple quiring a square wave the shortcomings output which is really better than that "probe" type designs. Injectors of this of this type of injector are many. The needed for a simple probe type injector. sort generally fall into one of two main square wave contains harmonics t- lots of categories. them. These are fine if you also want to FUNCTIONAL DESIGN On the one hand there is the very basic use the injector to pump a signal through It was decided early on in the develop- square wave type. In its discrete form it an r.f. stage working at 50MHz! But for ment of the Handheld Function Gener- usually consists of little more than a multi- audio circuit testing they can be a dis- ator that it should provide a reasonable vibrator using a couple of transistors, the tinct disadvantage, causing crosstalk and quality sine, triangle and square wave out- output being taken from the collector of breakthrough between stages. put with continuous coverage over most one of them. Using one of these injectors, while of the audio range. Also included is a The frequency might be a nominal 1kHz fault-finding in the pre-amp stages of an switched and variable output attenuator. or so. Often there is no control over the amplifier, the author actually managed to To -further increase its versatility the output level and this might be anything up get a weak but audible output from the output is via a small audio "power" type to 9V peak-to-peak depending on the bat- speaker, only to find that the power to he. With the output level set at maximum teries used. the amplifier was turned off! Confusing this allows the unit to drive low impedance indeed! loads, such as loudspeakers, directly. Finally, a square wave This could prove useful when testing source cannot be used in tests speaker wiring etc, in home and car audio for distortion. Using a square systems. The power available is only a few wave signal source tens of milliwatts but by selecting the when trying to square wave output, and adjusting the gen- trace distortion, X erator to a suitable frequency, a surpris- such as ingly loud output can be obtained. "clipping", is Finally, additional fixed outputs are completely available from the sine, square and triangle mind bogglingly signals. One or more of these could be T difficult if not connected to the circuit under test as well practically as say, an oscilloscope, a.c. millivoltmeter impossible. or frequency counter. In fact, where an Q On. Specification 'V Useable Frequency Range; From below 50Hz to over 20kHz, in three overlapping ranges Output Waveforms: (Output levels measured with fresh batteries fitted) Variable - Sine and Square wave. 0-300mV and 0-3V pk-pk Fixed - Sine and Square at nominal 500mV pk-pk Triangle at nominal 1 -SV pk-pk vf:,. Sine wave Distortion: Better than 5 per cent Full size Function Generator Power Source: 3V (2 x N-cells) fits easily in the palm of the Power Consumption: 5mA quiescent, rising to around 50mA at hand. full output into an 8 ohm load Everyday Practical Electronics, December 1998 875 accurate output level or frequency is The frequency on, each range is set by important, connection to one of these will control VR1, with resistor R3 acting as an —w TRIANGLEWAVE OUT end stop limiler. This resistor prevents stall- be a necessity. O Although the Handheld Function Gener- ing of the oscillator and excessive distortion ator is fairly comprehensive in its features - - SQUARE when VR1 is set to minimum resistance. see Specification panel - it must be stressed WAVE OUT The output on Range C tends to be slightly that it has not been possible to miraculously higher than the others so resistor R7 and squeeze the quality and features of a "full- lT> capacitor C6 are switched in to correct this. blown" instrument into such a tiny case. Overall, the output amplitude remains There are, of course, a number of trade-offs; substantially flat from 40Hz to 15kHz with for example the output amplitude, and to a a linear roll-off beyond this point. If an lesser extent, frequency are dependent on accurate level is needed, for say frequency supply voltage. response tests, then it would be prudent to With only 3V available a regulated sup- connect an A.C. Millivoltmeter or Oscillo- ply was considered impractical. Also, the scope to the SK2 output. distortion level of the sine wave is some- what higher than that of a "professional" Fig.2. Circuit arrangement for produc- generator. Even so, the unit should still ing a Schmitt oscillator. COMPONENTS find use in a number of applications where moderate distortion is of little consequence, Assuming resistors RI and R2 are the same Resistors such as in frequency response and gain value, say 5k6, then the period or frequency R1. R2, measurements in amplifiers, filters etc. and is set by the values of R3 and C. RIO 4k7 (3 off) in general purpose fault finding. R3, R14 3k3 (2 off) Frequency will then equal: R4 68k The additional fixed outputs and neat R5, R8, _ design of the case allow it to work as a quite I Hz R13, rib iok (4 off) See useable bench instrument as well. The gen- 2-2 x C x R3 R6 2k2 erator is powered by two inexpensive N- R7 100k XAI !/■ cells which will give many hours of service Again, assuming RI and R2 are the same R9 15k I ALIV under normal use. value, then the amplitude of the triangular R11, R12 150k (2 off) Page R15 6800 wave will be roughly two thirds of the dif- R17 10O HOW IT WORKS ference between — Vcc and + Vcc. Rl 8 Ik The main signal generator section is a All1 sW 5% carbon film Schmitt oscillator. This is a fairly simple CLIPPING In the Handheld Function Generator it is Potentiometers circuit and one in which the frequency can VR1 100k horizontal modular be altered quite easily. The Schmitt oscil- the triangular wave that is used as the basis carbon control (see text) lator is an adaptation of the more familiar for the sinewave and for this reason a VR2 1 k vertical modular carbon Schmitt trigger circuit, see Fig. I. fairly linear ramp is needed in order to control (see text) minimise distortion. If resistors R1 and R2 Capacitors are given suitable values the trigger level C1, C2 220m. sub-min. radial elect. A, O of the oscillator can be adjusted to produce 6-3V, 5mm lead OV a triangle wave of smaller amplitude. This spacing, 7mm high means that a smaller and hence more linear (2 off) > part of the exponential curve can be used, C3 330n polyester layer C4 33n polyester layer with a resultant output nearer to a true C5 2n2 polyester layer triangle. C6 330p plate ceramic The sine wave itself is produced through C7 470n polyester layer the simple but rather crude technique of C8 10On polyester layer "clipping" the triangle waveform to C9 10Op plate ceramic C10 non-polarised (see text produce a more sinusoidal shape. In for value) practice this is done by feeding the triangle waveform into a pair of signal diodes Semiconductors connected in inverse parallel, the non- D1,D2 1N4148 signal diode Fig. 1. Schmitt trigger circuit. (2 off) linear conduction characteristics of the D3 3mm red flashing l.e.d. In the Schmitt trigger a signal of slowly diodes progressively modifying the applied (SGG tGXt) varying amplitude is converted or "cleaned waveform. IC1 7621DCPA CMOS op.amp up" into one with a predictable output IC2 TDA7052 low-voltage amplitude. Signal levels below the set upper CIRCUIT DESCRIPTION power amp and lower trigger points are ignored. When The full circuit diagram for the Hand- Miscellaneous configured using an op.amp the upper and held Function Generator is shown in Fig.3. SI, S3 3-way double-pole lower trigger threshold points are set by Resistors Rl and R2 form a potential div- sub-min., p.c.b. ider to generate the OV rail, necessary for mounting, slide switch resistors R1 and R2. (2 off) The basic circuit exhibits a large de- the correct operation of IC1. ICla and its S2 2-way single-pole gree of hysterisis or "backlash" which con- associated components perform the function sub-min., p.c.b. siderably improves noise immunity. The of a Schmitt oscillator. mounting, slide switch upper and lower trigger points are affected, Capacitors C3, C4 and C5 set the SKI, SK2 3-5mm stereo screened to a degree, by the supply voltage and this three frequency ranges A. B, and C. The chassis jack socket coverage of these is approximately: 45Hz to (2 off) would, ideally, be stabilized. B1 1 -SV N-cell (2 off) An inverting Schmitt trigger can be con- 400Hz: 350Hz to 4kHz and 3-5kHz to Printed circuit board available from verted to a Schmitt oscillator by connecting 20kHz respectively. EPF PCS Service, code 213; miniature a resistor, R3, from the output back to the The upper limit on each range is partially sloping-front case, size 77mm x 44mm x inverting input, and a capacitor C from this limited to that which can be comfortably 28mm (max); probe tip; N-cell p.c.b. resolved, bearing in mind the small size of battery clips (2 sets); dual-gang shaft for point to ground (OV), as shown in Fig.2. VR1 and VR2 (2 off); miniature crocodile The resulting output is a high quality square the scale and control knob. Also, the scale clip; multistrand connecting wire; solder wave with, additionally at the mverting in- is non-linear and becomes more cramped etc. put, a "triangular" wave. towards the high frequency end. The ramp of the triangle waveform is On the prototype, the actual upper fre- actually exponential in shape and is produced quency limit reached on Range C was Approx Cost 1 by the charge and discharge of capacitor C 33kHz, The exact coverage of each range Guidance Only N through resistor R3 as the output switches will depend upon the lolerences of the excluding batt. alternately between -Vcc and -fVcc. individual capacitors used. 876 Everyday Practical Electronics. December 1998 As well as providing a small amount of gain. IClb buffers the triangle output at pin 2 of ICla. This gain is needed as the triangle wave produced is of insufficient amplitude to correctly drive the triangle to sine wave converter diodes D1 and D2. These diodes need at least 600mV to con- duct, although in practice they will begin to conduct at below 500mV. The high value given to resistor Rl I was found to give the best shape to the sine wave. Capacitor C8 isolates the two diodes from any d.c. offsets present at the output of IClb or input of IC2. Anything more than a few hundred millivolts will cause a d.c. bias to be applied to one of the diodes with resul- A 1kHz triangle waveform taken at A 1kHz smewave output taken from tant non-symmetrical clipping. Capacitor C7 IClb pin 7. IC2 pin 8. prevents any d.c. offset reaching the input (pin 2) of IC2. (1C2 input is referenced to the configuration gives a negligible d.c. offset A standard high brightness type could be negative line (— V) not OV). across the output (pins 5 and 8) and in nor- used instead if preferred. Resistors R12 and R13 form a potential mal applications a coupling capacitor is not divider to reduce the input level into IC2 to needed. COMPONENTS a suitable value. The actual level arrived at However, for a signal generator an out- It is important to use only the specified is designed to cause a very "soft" clip- put coupling capacitor is necessary as it iso- components for this project. The general ping action in IC2 which improves the sine lates the output from any d.c. that might be performance, and in particular the sine wave shape slightly. This clipping action present in the equipment under test. Also, a wave purity, will be adversely affected if increases marginally as the battery voltage capacitor here protects the equipment under different resistor values are substituted for falls, but is partially offset by the reduced test from the earth return path via resistor any of those around ICI a and ICI b or R11. input level to IC2. R17 and control VR2. Note that the output R12. The square wave output is produced pins of IC2 are effectively "floating" and Some alternative components may when switch S2 is closed. This connects neither should be earthed to the - V rail. simply not fit on the board. In particular the resistor RIO in parallel with resistors Rll Resistor R17 merely limits the available electrolytics Cl, C2 which must be no more and R12 and causes 1C2 to be driven hard output power, in the event of a short cir- than about 7mm in diameter. into clipping. Earlier attempts at making use cuit across the probe tip, with the attenuator switched out (Sib closed) and VR2 set to of the square wave available on pin 3 of v.[7 3 ICla yielded no better results than the maximum. Resistors R14 and RI5 form the simple method finally adopted. potential divider for the fixed 500mV output INPUT fT" 3 to socket SK1. TDA7052 To conserve battery life a Power On l.e.d. SIGNAL GND (_3_ 3 OUTPUT (D.3) is included as a reminder that the unit A bridge form of output stage is used is switched on. In the prototype a high N.c, fr" 3 by IC2 to generate relatively high power brightness flashing l.e.d. was used, the only levels at low supply voltages. The bridge type the author has any chance of noticing!. Pinouts for the TDA7052. ON/OFF Sla -cTND IfrequencyI R18 VR1 R3 100k 3k3 2 x 1.5V) B1 03 N-CELL 3V rWSr- -W-i R10 | sine/square] L I 4k7 n S2 r-W ^<^-1 -w 470n R11150k R12150k 7621IClb IC2 TDA R14 ^ R16 7621ICla 7052 3k3 10k Sib C8 I lOOn I C10 VARIABLE C1 C R171QQ (SEE_TF> OUTPUT 220M ■ R15 PROBE HP 680S) —W-i Rl ^ IleveU 4k7 4 1N4148- . 1N4148, GROUND I RANGE | RANGE 1 R8 CLIP 2K2 10k | FIXED OUTPUTS I | SINE/SQUARE I C3 Co R7 330n«■ 33n 330p momI 100k i] I C2 220m r 4K7 Fig. 3. Complete circuit diagram for the Handheld Function Generator. Everyday Practical Electronics. December 1998 877 IC1 • • \L • • • S2 • • 0 • 1>S • P • C8 i ' I* R18 T • • BATTERY •j • C2 • • C1 • +V IC2 •: vH2 s N / o L FIXED R15 R14 OUTPUTS .K' C10 S—I (SEE TEXT) TO GROUND TO PROBE CROC CLIP ► TIP Fig. 4. Twice-size printed circuit board topside component layout, together with interwir- ing connecting leads. Connections to SK1 and SK2 should be made from the back of the p.c.b. or the board can be drilled in an unpopulated area and the wires passed Component layout on the completed through the holes. The final size copper foil master pattern is shown top-right. circuit board. Only use the specified op.amp (a 7621) in If there is a requirement to use the gen- The batteries should still stay in posi- 1C1 position. Although some are quoted as erator to test low impedance loads with- tion as they fit fairly tightly in the case working at a 3V supply they either work out this low frequency limitation then €10 but any tendency for them to pop out of poorly or not at all below 3V. (Which must can be shorted out. A separate subminia- the contacts can be reduced by taping be allowed for as the batteries discharge). ture s.p.s.t. switch could be fitted in the them together before insertion in the The spec, on the ICL7621 indicates a mini- case opposite the two sockets in order to holder. Before soldering in the four mum supply voltage of ± 1V. facilitate this. To avoid possible damage to battery contacts the solder lugs should There are a number of alternative control IC2 or the equipment under test, it would be first be bent flush with the circuit board. shafts available for the controls used for VRI important to remember to return this switch If this isn't done the case back will not and VR2. The longer shaft is recommended to its "normal" position before using the close properly. as it has a serrated section at the end for function generator for general test work. MAKING CONTACT better grip. Because it is designed to go CONSTRUCTION through two pots, to make a stereo control, it The slide switches SI, S2, and S3 are is longer than needed and therefore the ex- Due to its compactness, great care will be raised off the circuit board by connector needed when building the Handheld Func- sockets on each pin. These sockets come cess should be cut off flush with the board. tion Generator. The positions of switches SI, S2, S3, presets VRI and VR2 require OUTPUT CAPACITOR accurate placing on the printed circuit board For normal use the output coupling in order to line up correctly with the front 38mm capacitor CIO should be a non-polarised or panel holes and cut outs. bi-polar type. A lOpiF 50V capacitor was All the components except capacitor CIO fitted in the prototype. This value is more and the two output sockets SKI and SK2 than adequate for feeding the output of the are mounted on one small printed circuit generator into medium to high impedance board (p.c.b.) while a separate miniature 23mm loads. However, to drive a low impedance p.c.b., containing spring contacts, holds the load such as a loudspeaker a much higher batteries. A twice-size component layout, value, say 470p,F, would normally be used. together with a full size foil master, is As mentioned in the circuit description, a shown in Fig.4. This printed circuit board, + - bridge type output like the one used in IC2 including batt. board, is available from the actually needs no coupling capacitor at all. EPE PCB Service, code 213. When using the generator to check out The use of a battery board (Fig.5) speakers and their wiring the effect of a low was necessary as a double N-cell battery value capacitor is to greatly reduce the holder could not be made to fit into the lower frequency output. case. The outside sections of each battery However, with the level at maximum and clip will have to be broken off otherwise Square wave selected, fast edged spikes or they will not fit into the battery compart- pulses are generated. Although these are not ment. These are quite brittle and by using a true representation of the output of the fine-nosed pliers a single bend at the generator they are still useful in producing a bottom of the clip should break off each Fig.5. Suggested battery p.c.b. dimen- very loud and distinctive output. "ear" leaving just the contact. sions and foil master. Everyday Practical Electronics, December 1998 unusually "horizon- PCB FROM FOIL SIDE tal" and "vertical" in this case refer to the control shaft and not the mounting.) Therefore, it is neces- HOLES A': 2mm DIAM. HOLE 'B' 7mm DIAM sary to mount VRI horizontally (with the shaft vertical), bend the two outer legs to go through the board il CASE FRONT DRILLING DETAILS CASE FRONT VIEWED ■>- (VIEWED FROM FRONT) FROM REAR 5mm SWITCH CUTOUTS EARTH LEAD PROBE HOLE SI. S32.5mm X 8mm HOLE DIAMETER 5mm S2 2.5mm X 7mm ,/ ■It AGAINSTGLUE CIO FRONT FLUSH PANEL ©2mm. I- SHAFT HOLES 6mm Q . BATTERY "*■ COMPARTMENT Fig.8. Case dimensions and drilling details, including top drilling for probe and "croc" lead. The output sockets are positioned in the side wall of the case lower section. Everyday Practical Electronics, December 1998 879 Layout of components inside the completed unit Table 1: Test Voltages showing wires to the output sockets. Note the plastic IC1 IC2 strip preventing the p.c.b. tracks from shorting on the Pin Pin screened jack sockets. 1 0V ±50mV 1 + 3 2 0V±50mV 2 OV 3 0V ±50mV 3 0V 4 -1-5V 4 N/C 5 0V ±50mV 5 + 1-5V 6 0V ±50mV 6 OV 7 0V ±50mV 6 N/C 8 + 1-5V 8 + 1-5V 2:. - Voltages taken with a standard 10 V megohm impedance Digital Voltmeter. Supply voltage + 3V. Range switch S3 set 2* to range B. Other control settings not y important. IC1 readings relative to 0V rail. IC2 readings relative to battery negative (-V). (0-6mm) permanent marker pen and a circle m template. The lettering and numbers were put on using Letraset rubdown transfers. These worked out rather expensive as the very small lettering used (l-7mm) appears to only be available in large sheets. With a little patience a perfectly acceptable job can be done using just the fine marker pen. These pens can be obtained from Art and Craft suppliers. The scale pointer is formed from a solid piece of fairly thick wire that is simply make a slot and then insert a flat needle are referenced to OV (use the "earth" pushed into a pre-drilled hole in the knob on file to enlarge the cutout to the correct connection from the triangle output for preset VR1. Don't forget to set VRI fully at shape. The approximate positioning of this) while voltages relating to IC2 are one end of its travel before drilling the hole, these cutouts is indicated in Fig.8. referenced to battery negative (- V). so that it corresponds with the end of the The probe comes in two parts; the tip The frequency coverage of each range scale. itself and an insulating cover. Solder a thick should agree approximately with the piece of solid-core wire to the tip before prototype, even allowing for varying IN USE pushing the cover on. This piece of wire tolerences of capacitors C3, C4 and C5. As the extreme upper limit of each range needs to be as stiff as possible to stop the An Oscilloscope or Frequency Counter is becomes cramped and distortion increases, probe from wobbling when in use. Glue the the best way to accomplish accurate due to changes in the duty cycle, the next probe into the centre hole in the top of the calibration although even with this the highest range should be selected and the re- case then cut the wire off about 1mm or smallness of the scale will mean that quired frequency obtained from this. so from the base and solder one end of only an approximate indication can be Note that the sine/square "grounds" capacitor CIO to it, see Fig.8. obtained. (SK2 and the earth clip) cannot be con- A pair of 3-5mm stereo sockets is used nected directly to the triangle output ground for SKI and SK2. The two centre connec- FINISHING OFF (SKI). However, these outputs can be tions on each socket are soldered together to The case as supplied is black so this was used simultaneously, feeding separate in- provide two mono outputs. painted grey using a car primer spray. Each puts, provided there is no common ground Various combinations of test leads can be of the three scales were drawn using a fine between them. made up depending on individual require- Finally, bear in mind that if the gen- ments. For example, two phono plugs at one erator is used for long periods of time end would provide an identical signal to the driving low impedance loads bat- left and right channels of a stereo amplifier. tery life will be reduced sub- Another possibility could be a phono plug stantially. on one lead and crocodile clips on the other. TESTING AND CALIBRATION After checking the board for dry joints and solder bridges, the 3V supply can now HiV \ be connected. Before doing this a mil- * liameter wired in series with one lead will prove useful in determining whether there V are any drastic problems with the board. The total quiescent current drain should lie between about 4mA and 6mA. If this reads OK then a check can be made for an output signal. Switch to Range B, set presets VR1 midway, VR2 to maximum and switch SI to Fli. Select the square wave output. A loudspeaker or earphone can now be con- V nected to the probe to check for an output; if working properly this will be at about 800Hz to 1000Hz or so and very loud. If nothing is heard refer to the test voltage Table 1 to aid with troubleshooting. Remember that all voltages relating to ICI 880 Everyday Practical Electronics, December 1998 The Alternative Oscilloscope Pico Technology provides an alternative to costly, bulky and complicated oscilloscopes. The ADC range of virtual instrumentation enables your PC to perform as an oscilloscope, spectrum analyser and digital multimeter. 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This series of although an understanding of fundamental electronic concepts articles:les will be of interest to anyone who wants to know how would certainly be an advantage. You do need, though, to have computers perform their magic, because it uses a unique mix of had some experience at assembling components onto a printed hardware and software to explain how computers work in a fun circuit board. You should also be moderately familiar with using a and interesting way. PC-compatible computer. ■ ello there! Last month we introduced Also last month, Alan Winstanley des- pull-down menu command, you'll discover H you to the phantasmagorical and cribed how to build a real PhizzyB from how to access the PhizzyB User Manual pedagogical PhizzyB Simulator. If you're the ground up. If you're not really into Volume I, which you can peruse on-screen new in town, PhizzyB stands for Physi- electronics, we have good news - you and also print out for your later reading cal Beboputer, a unique combination of don't need to be too much! This series is pleasure. hardware and software which creates a specially written for those who wish to Amongst other things, this document computer tutorial, demonstration and ap- know how computers really work. Essen- shows you how to use some of the plication system. tially, all you need to know is how to PhizzyB Simulator's tools and utilities, You can program a "virtual" Phiz- solder neatly and recognise components. including the Assembler, Memory Walker zyB on-screen by using the PhizzyB Alternatively, you can purchase ready- display and CPU Register display. If you Simulator Software running on your Win- assembled PhizzyBs - see later. haven't already done so, we strongly dows 95/98/NT personal computer. Then In this issue, Alan explains how to con- recommend you read this manual (it's only you can download your program to the real struct two very simple input/output (I/O) about 30 pages long) and perform the thing, the hardware PhizzyB which con- devices, which can be used to test the experiments therein before plunging head- nects via a null-modem cable to a serial PhizzyB's external I/O ports. For our part, first into the rest of this article. port on your computer (which must either we will be describing a suite of introduc- be COM I or COM2). tory programs that will both exercise these EXPERIMENT 1A The hardware PhizzyB can then be devices and teach you more about how the Testing ports $F010 and $F030 made to operate in the real world, perform- PhizzyB and PhizzyB Simulator work. Use Start -> Programs -> Phiz- ing a range of useful tasks using a versatile Note that you can perform all of zyB -> PhizzyB to invoke the PhizzyB array of input and output ports. these experiments using only the PhizzyB Simulator with the full version CD-ROM A demonstration copy of the PhizzyB Simulator, but they're a lot more fun if in your CD drive (or use Start -> Pro- Simulator was provided on the free CD- you have a real PhizzyB to play with as grams -> PhizzyBD -> PhizzyBI) if ROM accompanying last month's EPE. If well. you're still playing with the demo copy of you missed that great event, all is not lost One last point before we start. If you the simulator). because you can still order your very own invoke your PhizzyB Simulator and select Remember that the large board at the copy - see this month's Back Issues page. the Help -> Search on Help Contents bottom of the screen represents the main PhizzyB (see Fig.I); however, the large board you can see at the top of the screen £« '.H-JO Mooov tort; represents an expansion card for use in future projects. roo Now use the Tools -> Assembler command (or the "building block" icon) tm in your PhizzyB Simulator to activate the Counto m assembler and enter the program shown in Listing I. You'll also find it handy to BATE Power check last month's article for a refresh. Hi: I. It's not necessary to worry about enter- CTR1 ing spaces to make it look identical to List- ON ing I, but the commands must be typed IFffU ♦FOIO $F030 accurately as shown. Incidentally, the text M..M ACC PC after the hash (#) marks is merely to help with understanding. As you'll see, the first thing we do is to SP fuNZC assign labels to the internal input port at address SFOIO (which, you may remem- 4 FED IRQ Rv Fill ber, is the one connected to the 8-bit switch) and the two external input ports at lion addresses SFOl I and $F0l2. Similarly, we assign labels to the in- ternal output port at address $F030 (the *012 Fig. 1. The PhizzyB Simulator interface, represent- ing a real PhizzyB interconnected by ribbon cables to a variety of expansion boards. 882 Everyday Practical Electronics. December 1998 one connected to the 8-bit l.e.d. display) Continue to play with these switches un- Run command (or click the appropriate and the two external output ports at til your appetite is sated, then click the toolbar icon) to achieve the same effect. addresses $F031 and $F032. In fact we're Reset ("Rs") button to let the simulator Hence you can control the PhizzyB from only going to use the INPORTO and take a rest. your computer keyboard, or by using OUTPORTO labels in this experiment, but the corresponding switches on the circuit we'll be using the others a little later. EXPERIMENT 1B board. The .EQU directive means equates to Using the real PhizzyB As with the simulator, nothing seems to and this assigns the value shown to the In order to perform this experiment, you be happening initially, but once again the corresponding label. (Note that the use of must already have the fully constructed program is furiously racing around and labels and .EQU directives is introduced in hardware PhizzyB. Also, you need to be in around reading from the 8-bit switches and the PhizzyB User Manual Volume I.) possession of a full version of the PhizzyB writing to the 8-bit l.e.d. display. Try Following the constant label declara- Simulator on CD, because the demo copy flipping one or more of the 8-bit switches tions is the .ORG directive, which sets the does not contain the PBLink utility re- (on the real PhizzyB of course) and ob- start address of the program to $4000 (this quired to download programs to the real serve the corresponding bits respond on is the first location in the PhizzyB's RAM PhizzyB (you can purchase a full-blown the 8-bit l.e.d. display (note that the real - see last month's article for more details PhizzyB Simulator from EPE as detailed PhizzyB actually has a 10-bit l.e.d. dis- on this). later). play, but only the right-hand eight-bits are Next we declare an address label called If you don't have a real PhizzyB, you used). LOOP. We use an LDA (load ac- can proceed directly to Experiment 2 (al- Once your flipping frenzy has run its cumulator) instruction to load the ac- though it probably wouldn't cause you ir- course, you can either press the Reset cumulator from the 8-bit switches con- reparable damage to read this anyway). ("Rs") button on the real PhizzyB. or nected to input port SFOIO, then we use an But before we start, if you invoke your you can use the PBLink utility's Control STA (store accumulator) instruction to PhizzyB Simulator and use the Help - > -> Reset command (or click the ap- store the contents of the accumulator to the Search on Help Contents command, you'll propriate toolbar icon) to achieve the 8-bit l.e.d. display connected to output port discover how to access the PhizzyB User same effect. $F030. Manual Volume 2. Amongst other things, Finally we use a JMP (unconditional this document describes how to install the EXPERIMENT 3 jump) instruction to jump back to the label PhizzyB hardware and configure and use Testing input port $F()l I LOOP, at which point we start to do the PBLink software. Restore the assembler to its normal size everything all over again. If you haven't already done so, we (if you previously closed the assembler Once you've entered this program, use strongly recommend that you read this then activate it again and use it to open file the assembler's File -> Save As com- manual (it's only about 20 pages long) and aaexpLasm), then use its File -> Save mand to save this file as aaexpLasm, then perform the experiments therein before As command to save your program under use the assembler's File -> Assemble hurling yourself into the rest of this the new name of aaexp2.asm (thereby command (or click the appropriate toolbar experiment. creating a duplicate of the program). icon) to assemble this program, which will OK, before you do anything else, be All we're going to do in this experiment cause the assembler to generate a machine sure to use a null-modem cable to con- is to modify the LDA instruction such that code file called aaexpl.ram. You'll hope- nect your PhizzyB to either the COM I it now reads from INPORT1 (the input fully see the message "Your file was as- or COM2 port on the back of your PC port at address $F0l I): sembled without error!" at the bottom of (see this month's Circuit Surgery for more the Assembler/Editor window. details on null-modem cables). LOOP: LDA [INPORTl] Listing 1 Now use the assembler's File -> INPORTO: • EQU $F010 #Assign a label to input port $F010 Assemble command to assemble this new INPORTl: • EQU $F011 #Assign a label to input port $F011 program, followed by the simulator's INPORT2: -EQU $F012 #Assign a label to input port $F012 Memory -> Load RAM command to OUTPORTO: • EQU SF030 #Assign a label to output port $F030 load the resulting aaexpl.ram machine OUTPORT1: • EQU $F031 #Assign a label to output port $F031 code file into the simulator's memory, then OUTPORT2: .EQU $F032 #Assign a label to output port $F032 click the simulator's Run button to execute this new program. .ORG $4000 #Set start address to $4000 Try clicking the PhizzyB Simulator's LOOP: LDA [INPORTO] #Load accumulator from input port 8-bit switches. Not surprisingly, nothing STA [OUTPORTO] #Store accumulator to output port happens, because our new program is no JMP [LOOP] #Jump to label LOOP and do it again longer reading from this input port. In- • END stead, the program is now reading from the external port at address $F0l I. Minimise the assembler to get it out of Note that the PhizzyB's PBLink utility If you look at the simulator's interface, the way, then click the Power button on uses COM2 by default. If you are already you'll see a representation of a small cir- the PhizzyB Simulator interface to power- using your COM2 port for something else, cuit board at address $F0l I (Fig.2). This is up the simulator. Use the simulator's then you can connect your PhizzyB to a generic device that we can use to repre- Memory -> Load RAM command to COM I, but you'll have to configure the sent almost anything we might wish to invoke a dialog offering a list of the PBLink utility appropriately (this process connect to this port (we'll discuss this programs that are currently available. is discussed in the PhizzyB User Manual aspect of things in more detail in future You'll see the new aaexpl.ram file in the Volume 2). articles). scrolling list on the left-hand side of the Now connect the PhizzyB's power sup- Note that this generic input device has display, so double-click this entry to add it ply, and note that the various displays three fields. The top-most field is prefixed to the right-hand list. briefly flash in exactly the same way as by a character, which is used to Now click the dialog's Load button to did the simulator's displays. Use the indicate that this field represents a bi- load the contents of aaexpl.ram into simulator's Tools -> PhizzyB Interface nary value. The middle field is prefixed the simulator's memory, then click the command to invoke the PBLink utility. by a "$" character, which indicates simulator's Run ("Ru") button to execute Next use the PBLink utility's File -> a hexadecimal value. The bottom field the program. Open command to load the newly-created doesn't have a prefix, which means this Initially, nothing seems to be happening, aaexpl.ram file, then use the File -> field represents a standard decimal value. but in fact the program is furiously racing Download command (or click the ap- Use your mouse to select the top field, around and around reading from the 8-bit propriate toolbar icon) to download this enter a binary value of OOIIOIOI, and switches and writing to the 8-bit l.e.d. dis- program to your PhizzyB. click the board's Set button. The act of play. Click one of the 8-bit switches and In order to run this program on the clicking the Set button formally presents note the corresponding l.e.d. light up on the hardware PhizzyB, you can either press the the new value to the input port, at which output display. Note that the switch ac- Run button on the real PhizzyB, or you point our program can see it and light the tuators are coloured red on the simulator. can use the PBLink utility's Control -> corresponding l.e.d.s on the 8-bit display. Everyday Practical Electronics, December 1998 883 £fc y««*y lodh He*. ■ -i^I »i ?<*»(• l/ctsUv Mw«3 CA»€ ifrf4 6AU: «ff4 Cffi|| :-. lime « CIRI it#! OKI- X IfJ? I nmn**** tfff; c.«y ■■B Hi oooooooo ocnooooo t art . [Rfrrt Fig.2. Generic input device at port $F011. Fig. 3. Generic output device at port $F031. Also, clicking the Set button causes the program under the new name of Now use the PBLink utility to open hexadecimal and decimal fields on the aaexp3.asm. Next modify the LDA aaexp4.ram and download this program to board to be updated with their equivalent instruction such that it reads from the PhizzyB. Press the Run button, and values. In fact you can enter your data into INPORT2 (the input port at address ensure that everything is working correctly whichever held is the most appropriate for $F012) and assemble this new program. in the real world (note that the left-most whatever you're trying to represent at the Follow the remaining instructions from switch on the 8-bit switch device cor- time: for instance, entering %11111111 Experiment 2, but this time test the input responds to the bottom-most l.e.d. on the produces $FF or decimal 255. Experiment port at address $F0I2. described output board, and so forth). by entering a few more values, then click the simulator's Reset button. EXPERIMENT 4 EXPERIMENT 5 In order to demonstrate this particular Testing output port $F031 Testing output port $F032 program on the real PhizzyB hardware, it's Use the assembler to open the original Save your aaexp4.asm program under necessary to construct a real I/O board as aaexpl.asni program and save it under the the new name of aaexpS.asm. Now modify described in this month's constructional new name of aaexp4.asm. This time we're the STA instruction such that it writes to article. A multi-purpose generic I/O board going to modify the STA instruction such OUTPORT2 (the output port at address is described which enables you to fabricate that it now writes to OUTPORT1 (the $F032) and assemble this new program. simple input and output circuits and then output port at address $F031): Follow the remaining instructions from connect these to the appropriate PhizzyB Experiment 4, but this time test the output ports using a ribbon cable connector. STA [OUTPORT1] port at address $F032. The idea behind the following experi- ments is to test the operation of the in- a put and output ports of your constructed PhizzyB, using a simple switch input and _b simple l.e.d. bargraph output, each built on E> a b a PhizzyB I/O board. V a b y a b V Now would be a really good time to 0 0 0 0 0 0 0 0 n connect a real 8-bit switch to the PhizzyB's 0 1 0 0 1 1 0 1 i external input port at address $F011 (it's 1 0 0 1 0 1 1 0 f good practice to power down the PhizzyB 1 1 1 1 1 1 1 1 0 while you're connecting external devices). (a) 2-input AND Then power up the PhizzyB, use the (b) 2-input OR (c) 2-jnput XOR PBLink utility to open your aaexp2.ram tile and download it to the PhizzyB, and Fig.4. The AND. OR and XOR logic gates. press the PhizzyB's Run button. Assemble this new program, use Try flipping each of the 8-bit switches the simulator's Memory -> Load EXPERIMENT 6 in turn and note the corresponding l.e.d. RAM command to load the resulting AND instruction lights up on the 8-bit display (the bottom aaexp4.ram machine code file into the Digital computers are constructed using switch corresponds to the right-most l.e.d., simulator's memory, then click the large numbers of primitive logic gates, and so forth). simulator's Run button to execute the three of which are known as AND, OR, In fact, the top-most switch (numbered program. and XOR (Fig.4). I) is the Most Significant Bit (MSB). The Try clicking the PhizzyB Simulator's In the case of the AND (Fig.4a), the bottom-most switch (numbered 8) is the 8-bit switches and observe that nothing output "y" is only "True" (logic 1) if Least Significant Bit (LSB). This matches happens on the 8-bit l.e.d. display, because holh inputs "a" and "b" are True, other- the numbering scheme of SFOIO on the we're no longer writing to this port. In- wise the output is "False" (logic 0). main PhizzyB board, where switch number stead, the fields on the generic output By comparison, in the case of the OR 8 on the right is the LSB, to tally with board connected to the external port at (Fig.4b), the output "y" is True if either the l.e.d. display $F030 in which the right- address $F031 update to reflect whatever "a" or "b" are True. In fact, this type hand l.e.d. is the LSB of the binary value value is currently on the switches (Fig.3). of OR should more properly be called an displayed. Experiment by entering a few more inclusive-OR, because the input combina- Don't forget to reset your PhizzyB when values, then click the simulator's Reset tions that cause "y" to be True include the you've finished. button. Once again, if you have a real case where both "a" and "b" are True. PhizzyB, now would be a real good time Contrast this with the XOR or exclusive- EXPERIMENT 3 to connect the simple 8-bit l.e.d. output OR (Fig.4c), in which "y" is only True if Testing input port $F012 device (see this month's constructional just one input is true, and which therefore Use the assembler's File -> Save As article for details) to the PhizzyB's exter- excludes the case where holh of the inputs command to now save your aaexp2.asm nal output port at address $F031. are true. 884 Everyday Practical Electronics, December 1998 i 11 Q| iToTTfb |1 |oi "'I "10 [ I'fo 1110 [ 11 o| jTTbTi Toll |0|1 lot Similarly, if you set the external port to a binary value of 11111111, then whatever AND OR ^XOR value you set on the 8-bil switches is inverted. Examine the truth table in roIoTofol iTi'f'1'111 j 010101011 i 1; 1111 oio'ololiiiiilii Fig.4c and the illustration in Fig.5c and make sure that you understand why this ^ = 4 = n is so. (Don't forget to reset both the simulator and the real PhizzyB when i o Io Io|"o111oriTol pTTbHTb11 l iTiTil 11'|oTiToIoI ilol'i I you've finished.) (a) AND (b) OR (c) XOR NOT, NAND, NOR AND XNOR Fig.5. The AND, OR and XOR instructions. The ability to invert a value by XORing it with another value of all Is can be very The reason this is of interest to us is If you have a real PhizzyB, connect the useful, particularly in the case of the Phiz- that a computer's Central Processing Unit simple input switch to the external port at zyB. In addition to the AND, OR and (CPU) supports a set of instructions known address $F011 and use the PBLink utility XOR as discussed above, many CPUs sup- as logical instructions, so-called because to download your aaexpb.ram file to the port a NOT instruction that inverts the they perform essentially the same logi- PhizzyB. Then check that the AND in- contents of the accumulator (that is, swaps cal operations as do our primitive gates struction works the same way in the real the 0s for Is and vice versa), and also the (Fig.5). world. (Don't forget to press the PhizzyB's NAND, NOR, and XNOR instructions, Remember that the PhizzyB Reset button when you've finished.) which stand for Not AND, Not OR and predominantly works with chunks of data exclusive NOR, respectively. that are 8-bits wide, which is why this EXPERIMENT 7 However, when we designed the Phiz- figure features 8-bit quantities. These OR instruction zyB we wanted to make it as simple as logical instructions may be referred to as Use the assembler to save aaexpb.asm possible, so it only supports the AND. OR, bitwise operators, because they perform to aaexpT.asm, change the AND instruc- and XOR instructions. But turn that frown their magic on a bit-by-bit basis. tion to an OR, assemble this new program upside down into a smile, because all is In the case of the AND, for example, to generate the corresponding aaexpT.ram not lost and your quality of life is not bit[0] of the first field is ANDed with file, and load this file into the simulator's going to suffer. bit[0] of the second field to generate bit[0] memory. As we've seen, we can effect the same of the result, bit[l] of the first field is Run this program and use the values functionality as a NOT instruction by ANDed with bit[ 11 of the second field, and shown in Fig.5b to test that the OR in- XORing the contents of the accumulator so forth. struction functions as expected. Experi- with all Is. Let's call this a pseudo-NOT. It In order to see these instructions "in the ment with some other values until you're therefore follows that we can implement a flesh" as it were, bring up the PhizzyB's happy that the OR holds no further mys- NAND by performing an AND followed assembler and enter the program shown in teries, then click the simulator's Reset by a pseudo-NOT, and similarly for the Listing 2. button. NOR and XNOR functions. CPU STATUS Listing 2 REGISTER INPORTO: EQU $F010 #Assign a label to input port $F010 In Part I we noted that the PhizzyB's INPORTl: EQU $F011 #Assign a label to input port $F011 CPU contains an 8-bit register called the OUTPORTO: EQU $F030 #Assign a label to output port SF030 accumulator (ACC), which it uses to store (accumulate) intermediate results. In fact ORG $4000 OSet start address to $4000 the CPU also contains another register LOOP: LDA [INPORTO] #Load accumulator from input port 0 called the. status register, where the bits AND [INPORTl] #AND the contents of the accumulator forming the status register are commonly #with the value from input port 1 STA [OUTPORTO] #Store accumulator to output port referred to as status bits or status flags JMP [LOOP] #Jump to label LOOP and do it again (Fig.6). ■ END Due to the fact that we may require to load the status register from the memory (or store its contents in the memory), it is Save this file as aaexpfi.asm, assemble As usual, if you have a real PhizzyB. usual to regard this register as being the it to generate aaexpb.ram, use the download aaexp7.ram and test this pro- same width as the data bus (eight bits in Memory -> Load RAM command to gram in the real world (don't forget to the case of the PhizzyB). load aaexpb.ram into the simulator's press the PhizzyB's Reset button when However, the PhizzyB only actually memory, and click the Run button to you've finished). employs five status flags, which occupy execute this program. the five least-significant bits of the status Now enter the value 10101010 into the EXPERIMENT B register. This means that the three most- external input port at address SFOI1 (don't XOR instruction significant bits of the register exist only in forget to click the Set button) and set the You know the drill by now! Use the as- our imaginations, so their non-existent 8-bit switches (input port address $F010) sembler to save aaexp7.asm to aaexpS.asm. contents are, by definition, undefined. to reflect a binary value of 00001 111. Ob- change the OR instruction to an XOR, as- This month we are only going to con- serve that the 8-bit l.e.d.s show a binary semble this new program to generate the sider two of the PhizzyB's status flags: the pattern of 00001010 as was predicted in corresponding aaexpS.ram file, and load this negative (N) flag and the zero (Z) flag. Fig.Sa. file into the simulator's memory. Negative (N) Hag Swap the values between the two input Run this program and use the values The negative (N) flag, which is also ports and observe that the result remains shown in Fig.Sc to test that the XOR called the sign flag, typically contains a the same. This is because the AND func- instruction functions as expected. As copy of the most significant bit in the tion is "commutative," which means that usual, if you have a real PhizzyB, accumulator following an operation on the the result of the operation is not affected download aaexpS.ram and test this computer. by the order in which we specify the input program in the real world. This flag is called the negative flag values (this is also true for the OR and Note that if you set the 8-bit switches to because a logic 1 in the most-significant XOR functions). a binary value of 11111111, then whatever bit of the accumulator indicates a negative Experiment with different values until value you enter on the external port is in- number (this assumes that the value in the you're confident you understand how this verted (all the 0s are changed to Is, and accumulator is being regarded as a signed, flavour of the AND instruction works, then vice versa), as can be seen on the 8-bit two's complement value - we'll discuss click the simulator's Reset button. l.e.d. display. signed numbers next month). Everyday Practical Electronics, December 1998 885 Zero (Z) flag our purposes here, we need only note right-most bit on the 8-bit l.e.d.s at out- The zero (Z) flag is predominantly used that the LDA instruction occurs at address put port $F030 light up. Then click Step to indicate whether or not the accumulator $4000, the STA appears at address $4003, once again to execute the JMP instruction, contains a value of zero following an and the JMP ends up occupying address which again returns us to address $4000. operation on the accumulator. However, $4006. Now click the left-most switch on the we should note that this flag is also used Use the simulator's Memory -> Load 8-bit switch and click the Step button to to indicate the presence or absence of RAM command to load the contents of load this new value into the accumulator. a zero condition in the index register aaexp9.ram into the simulator's memory. Remembering that the negative (N) flag following INCX (increment index reg- As you will recall, this program loops typically contains a copy of the most sig- ister) or DECX (decrement index register) around loading the accumulator with the nificant bit in the accumulator following instructions. value on the 8-bit switches connected to an operation on the computer, it should The zero flag is also used to indicate the input port at address $F0I0, and writ- come as no great surprise to see that the whether or not two numbers are equal fol- ing these values to the 8-bit l.e.d. display negative bit lights up on the status register lowing a CMPA (compare) instruction. connected to the output port at address display. $F030. Experiment by setting other values on Before we execute this program, en- the 8-bit switch and stepping through the sure that all of the 8-bit switches are in program until you are confident that you their off positions (that is, with the red understand how these two flags function CP (insofar as the context of this experiment). I - Interrupt mask flag Assuming that you have one, it would be O » Overflow flag a good idea to download this program to N ■ Negative (sign) flag your real PhizzyB and to repeat this ex- Z - Zero flag periment in the real world. Don't forget to C - Carry flag reset the simulator and the PhizzyB when you're done. 0 rv EXPERIMENT ID Conditional jumps Fear not my braves, because this is the last of our experiments for this month (phew!). One of the main reasons that computers are so powerful and versatile is Fig.6. The Status Register l.e.d. display used on the hardware PhizzyB. that they have the ability to determine Note the 8-bit l.e.d. display just to the bits towards the bottom). Now, as op- future actions based on the results of pre- right of the 7-segment displays on the posed to using the Run button, click the vious operations. simulator interface. The 5-bits marked simulator's Step ("St") button instead. The way in which this works is that "I", "N", "Z" and "C" reflect the This causes the simulator to step through the CPU understands special instructions current contents of the corresponding flags the first instruction which loads the value called conditional jumps. This means that in the status register. With regard to these on the switches into the accumulator. these jump instructions will only occur if flags, we also need to be aware of a Note that the program counter (PC) specific conditions are True, and these convention as follows: 7-segment displays now show a value of conditions are based on the values of the • A status flag is said to be set if it $4003, which is the address of the next status flags. contains a logic 1, which is used to indi- instruction to be executed (the STA in this Remembering that we're only consider- cate a True condition. For example, if the case). More importantly, the zero (Z) flag ing the zero (Z) and negative (N) flags at zero flag is set (contains a logic 1), this on the 8-bit status register display has lit the moment, there are four conditional indicates that: It's True to say that the up to indicate that the accumulator now jump instructions associated with these current value stored in the accumulator is contains a zero value. flags: zero (that is, all of the bits in the ac- Click the Step button again, which cumulator contain logic Gs). causes the value in the accumulator to be JZ = jump if zero (jump if the zero flag is • A status flag is said to be cleared if it stored to the 8-bit l.e.d.s at output port True/logic I) contains a logic 0, which is used to indi- $F030 (the reason nothing seems to hap- JNZ = jump if not zero (jump if the zero cate a False condition. For example, if the pen is that the accumulator contains zero flag is False/logic 0) zero flag is cleared (contains a logic 0), of course). Note that the PC displays JN = jump if negative (jump if the nega- this indicates that: ITs False to say that the update to show a value of $4006, which is tive flag is True/logic 1) current value stored in the accumulator is the address of the next instruction to be JNN = jump if not negative (jump if the zero (that is, one or more of the bits in the executed (the JMP). Now click the Step negative flag is False/logic 0) accumulator contain a logic I). button one more time, which executes the Unfortunately, this convention can ap- JMP instruction and returns us to address To understand how this works, we're pear somewhat counter-intuitive (espe- $4000. going to write a simple program that reads cially in the case of the zero flag) and it Click the right-most switch on the 8-bit a value from the 8-bit switches connected takes a little effort to wrap your brain switch, and note that nothing happens to to the input port at address $F010, and around it the first time you see it, but the zero flag because we haven't loaded writes this value to the 8-bit l.e.d.s con- you'll find that it really does make a lot of this value into the accumulator yet. Now nected to the output port at address $F030. sense once you get into the swing of click the Step button to execute the LDA But there's a twist, because if the left- things. Trust us on this, have we ever lied instruction, and note that the zero flag most switch is on (which means that it's to you before? (Don't answer that!) is extinguished, because the accumulator connected to a logic 1), then we're going now contains a non-zero value. to invert the value (swap 0s for Is and EXPERIMENT 9 Click the Step button once more to ex- vice versa) before we write it to the 8-bit Zero and negative flags ecute the STA instruction, and observe the l.e.d.s. Activate the PhizzyB's assembler, open your original aaexpl.asm file, save this file under the new name of aaexp9.asm, then assemble it to generate the cor- responding aaexp9.rain tile. Before you 00008 .ORG $4000 00009 4000 91 F0 10 LOOP: LDA [INPORTO] do anything else, use the assembler's 00010 4003 99 F0 30 STA [OUTPORTO] Window -> View Listing File command 00011 4006 C1 40 00 JMP [LOOP] to look at the corresponding list file aaexp9.lst (Fig.7). List files are discussed in more detail in the PhizzvB User Manual Volume I. For Fig. 7. Part of the list file for program aaexpd. 886 Everyday Practical Electronics, December 1998 ( Begin \ Listing 3 INPORTO! .EQU $F010 #Assign a label to input port $F010 OUTPORTO: Load ACC • EQU $F030 #Assign a label to output port $F030 from SFOIO | ■ ORG $4000 #Set start address to $4000 LOOP: LDA [INPORTO] #Load accumulator from input port 0 JNN (STORE) #If N=0 jump to label STORE XOR $FF #.. otherwise invert contents of ACC / l8"N"\ STORE: STA [OUTPORTO] UStore accumulator to output port no JMP [LOOP] flJurap to label LOOP and do it again <( flag true • END \ 7 S Enter the program shown in Listing 3 Starting from scratch, create a program 1 yes into the assembler, save it under the name that loops around loading the accumulator XORACC j of aaexplO.asm, assemble it, load it into with values from the 8-bit switch. Depend- with $FF the simulator's memory, and run it. ing on whether the left-most switch is off Experiment by placing different patterns or on, AND or OR the value in the ac- i on the 8-bit switches and observe that cumulator with whatever value is present Store ACC whenever the left-most switch is in its on on the input device connected to the exter- to $F030 position, the resulting pattern appearing on nal port at address SFOl I. Then display the the 8-bit l.e.d.s is the inverse of the pattern result on the output device connected to l r on the switches. When you are happy that the external port at address $F031. this is so, download this program to the Now use the simulator's Help -> Jump back 1 PhizzyB and ensure that it functions the to $4000 | Search on Help Contents command to same way in the real world. activate the online help, and then select the item in the main page marked The Official Fig. 8. Flowchart for program aaexpW. HOMEWORK AND Beboputer Microprocessor Databook. We FURTHER READING strongly recommend that you read its You probably feel pretty confident that Appendix D, because this Appendix con- Consider the flowchan in Fig.8 and you're on top of things at the moment, tains a rather useful introduction to the compare it to the code in Listing 3. As per but it's always easy to do something when Beboputer's (and hence the PhizzyB's) some of our earlier programs, the first you're following someone else's instruc- assembly language. thing we do is to load the accumulator tions, so let's see just how much your con- with the value on the 8-bit switches. The fidence is justified, shall we? RESOURCES act of loading the accumulator automati- The following items are available from cally updates the zero and negative status MET thle EPE PCB Service at the Editorial ad- flags. . w\ dress (prices include VAT and P&P): For the purposes of this particular pro- Full working version of the PhizzyB gram, we want to check to see if the most- CD-ROM £14.95 significant bit in the accumulator is a logic / ||f I. We know that the negative flag is a Pre-programmed PhizzyB micro- copy of the most-significant bit in the ac- controller £14.95 cumulator, so all we really have to do is to ■ COMPACT PhizzyB printed circuit board, check the value of this flag. mm £14.95 If the negative flag is False (contains a disc V :" The two amazing books referred to last month, logic 0), then all we want to do is to store Interactive the value in the accumulator to the out- Bebop Bytes Back and M "f'' Bebop to the Boolean put port driving the 8-bit l.e.d.s. But if the Use File > Open on your / / } ontrose negative flag is True (contains a logic 1), Web browser to open Boogie, are available from defautt.htm on tht* CD ueractfoe the Direct Book Service then we want to invert the value in the (or use Notepad to read www-rn axm on.com (see their pages elsewhere accumulator before we store it. the weicome.txt file). One way to achieve this is to use a JNN in this issue). {jump if not negative) instruction, which will jump to a specified location if the THERE'S MORE negative flag contains a logic 0. However, The PhizzyB 'Simulator Next month we will intro- (c) 1998 Maxfleid & Montrose Interactive inc duce the carry (C) and over- if the negative flag contains a logic 1, AH Rights Reserved flow (O) flags, unsigned and then the JNN will fail and the program signed binary numbers, and the will simply proceed to the next instruc- stack and subroutines. The accompany- tion, in which we invert the contents ing constructional project will show you of the accumulator by XORing how to build a simple liquid crystal display them with a value of all Is (l.c.d.) output board, and we'll be using ($FF in hexadecimal = our new found knowledge of subroutines 11111111 in binary) w to create a program to drive this little rascal. Last, but not least, we'll introduce a little PhizzyB programming competition, the winner of which will receive a year's Si free subscription to EPE. Until then, we remain . . . fond of ice cream! Best regards. Max and Alvin. Be sure to check out this month's con- structional article, which follows next. BEE-LINE Computer simulation Max and Alvin would love to hear of the assembled from you via their web site: PhizzyB printed circuit board. http://www.maxmon.com. Everyday Practical Electronics, December 1998 887 Understanding Computers —— x u i'''\ z^'- PhizzyB COMPUTERS Construction - Input and Output boards v —^ — /\jan winstanley Adding outside world communication options - input control switches and an i.e.d. bargraph. In Part 1 last month, we introduced the Further down the road, we will be in- MULTIPURPOSE PhizzyB Simulator software, which troducing a variety of applications which runs on an IBM-compatible PC com- utilise the I/O ports of your PhizzyB. I/O BOARD puter under Windows 95/98/NT. The con- It is again highlighted that the PhizzyB is A specially-designed PhizzyB I/O board structional details for the real hardware a commercial product and the purpose of is available which can be cut into four sec- PhizzyB were also provided. this series is to construct and use the tions (see Fig.I). Each section can carry a This month's practical article describes software and hardware to emulate the 20-way connector next to the prototyping a simple prototyping I/O (input/output) operation of a real computerised control area and is suitable for both input and out- board which can be used to connect system. put add-on circuits. The 20-way connector external circuits directly to your hardware Outline circuit diagrams of the I/O mod- is hooked over to a PhizzyB input or out- PhizzyB. This test board allows sen- ules are provided here, but otherwise the put port using a ribbon cable. sor transducers, switches and other com- operation of the PhizzyB computer is Having divided the board into quarters ponents to be interfaced directly with a beyond the scope of this educational series. (see later), there is one important PhizzyB. difference between them, which Apart from introducing some is that a single continuous row of assembler and programming tracks (often called a "busbar") techniques, one of the purposes may either be at the top of a of the experiments in Part 2 is to section ("A") or at the bottom confirm that the I/O ports on liffti'it" ("B"). This "A" and "B" your PhizzyB really do work. tSfs'sH i notation helps to ensure that the They can be tested simply by "correct" board is utilised by connecting a bank of switches to readers, as determined by where an input port, and an I.e.d. array the busbar actually is. to an output port. The four boards can each be By downloading the relevant used for either input or out- .ram program from the PC 11 put experiments. Constructors to your PhizzyB, you can should ensure they use the soon show that the I/O ports "correct" board section to are functioning as expected. correspond with our drawings. Then, by changing the program * It is perfectly feasibly merely and reloading the corresponding to cut the board in half (rather .ram file, you can swap the I/O than into four) and use each circuits to other ports and prove section independently, as we did that they operate correctly, as in this month's experiments - well. Assembled Simple Switch Input board. see photos. Spare sections can be 2 , o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o-o 4 „3 cro—o " o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 3 • • tfo—o ? o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 6 • • cro—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 10 7 cr o—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 12 „ cro—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 14 (A) cr o—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o cro—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 15 • • o- o—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 20 17 cro—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 19 • • cro—o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o cr o—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o cro—o _ o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o cro—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o # cro—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o J*1 •* (B) cro—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 13 • • cr o—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 15 • • cro—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 17 cro—o ° o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o 19 cro—o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o o-o-o ooo-o-o-o-o-o-o-o-o-o-o-o-oo-oo-oo-o Fig. 1. Two sections of the 4-sectloned PhizzyB I/O board: (left) component side view, (right) trackside view. 888 Everyday Practical Electronics. December 1998 8 WAY SPST DIP SWITCH +5V (SLIDE) +5V 1 2 IRQ IACK 3 d N IP7 5 C^O IP6 7 IPS 9 TO 20 WAY IP4 11 CONNECTOR IP3 13 14 CON1 IP2 15 16 IP1 18 y IPO 20 N.C. cfc INPUT PORT 20-WAY CONNECTOR -O N C. (CON 1) OV (COMMON) AERIAL VIEW R1 OF PINS 9 x 4k7 Fig.2. Circuit diagram for the Simple Switch Input board, plus 20-way input connector pinout details. BUSBAR -A (A) 10 12 (A) fcurl i—I 14 13 15 (B) 17 CUT —[cun _ (OPTIONAL) (A) SPOT 1 S1 16 * TcutI _ LI • tn i • • n~i i • 4^ (B) INPUT SWITCHES • n i • NOTCH • fn i • 10> BOARD • m i • (B) The circuit diagram for the Simple • ii i i • A PHIZZYB I/O BOARD • II i i • MAY BE DIVIDED INTO Switch Input test board is shown in Fig.2. —• FOUR INDIVIDUAL • II i i • * * BOARDS. This consists of an 8-way dual-in-line ON ► 10 (d.i.l. or d.i.p.) switch, SI. You will see 19 CON1 20 that the inputs to all eight switches are wired to -(-5V via pins 1 to 8, and their BUSBAR outputs run directly to a 20-way connector Fig.3. Component layout and connections for the Simple Switch Input board. Note that links over to the PhizzyB (IPO to 1P7). that section "B" is used (the cutting details are shown on the right). The switches can be closed to con- nect their corresponding outputs to +5V looking at the top side of the board - non- (representing a logic I to a real Phiz- track side). File the board edges smooth. zyB input port). So, by closing all eight COMPONENTS Two "B" type boards are used for this switches, you would input the binary num- month's demonstrations. ber 11111111 to a PhizzyB - always as- Resistors Start assembly by soldering the 20-way suming you've programmed it properly to R1 4k7 9-resistors s.i.l. IDC header into position on a type "B" read from that input port! module (Bourns board. Look closely to locate pin 1 of the 4610X-101) connector, referring to the notches on the Furthermore, all the switch outputs are R2 15011 9-resistor module connected via a 4k7 (4-7 kilohms) resistor (Bourns 4610X-101) moulding, or look for a small arrowhead to network (Rl) to 0V. This is a way of en- denote pin 1. (See Fig.3.) suring that the input lines IPO to IP7 are Semiconductors The connector should be level against IC1 74LS540 or 74ALS540 usually tied low to 0V and are never left octal buffer the board - use a small piece of Scotch "floating" (unconnected to anything). The BAR1 10-segment d.i.l. red l.e.d. tape (or similar) to hold it in place tem- resistor network is self-contained within a bargraph porarily during soldering. Each solder joint should take one or two seconds only and single-in-line (s.i.l.) package. Miscellaneous Commence construction by cutting a S1 8-way s.p.s.t. d.i.l. switch use only 2mm or so of fine gauge solder new I/O board into its four sections. Start CON1, (e.g. 22 s.w.g.). Take extreme care to en- by cutting along the middle row of holes CON2 20-way IDC non-latching sure that you do not bridge adjacent joints specially provided to help with this. Use a box header (2 off) with excessive amounts of solder. "Junior" hacksaw or (e.g.) a Dremel cut- PhizzyB I/O board type "B" (2 off) Next, solder into place the d.i.l. switch, - cut from 4-section I/O board (see followed by the s.i.l. resistor. Position the ting disc, and slice the board to produce text), available from the EPE PCS Serv- two boards. ice, code 216 (I/O Board); 20-way 0-05- components in the suggested locations as You may then proceed to further divide inch IDC connector (4 off); 20-way 0-05- shown in Fig.3. The resistor array has a these boards into two if desired, in which inch IDC cable, approx 30cm; solid-core polarity marking, with pin 1 (the "com- case it's a good idea to label each one as hook-up wire; solder etc. mon" pin for the nine internal resistors - an "A" type or "B" type board. Type one resistor is unused) signified by a dot. "A" boards have the busbar at the top, Ensure it is orientated correctly. Approx Cost Close inspection of the board reveals that type "B" have it at the bottom (with the Guidance Only IDC connector facing to your right when its copper track pattern is formed into Everyday Practical Electronics, December 1998 889 "triplets" - a matrix of pads, each being drive l.e.d.s directly through current-limit- three holes connected together. There is ing resistors. also one continual copper track (the busbar The chip should be treated as static sen- referred to earlier), which can be used as a sitive, so anti-static precautions are wise power supply "rail" (for + 5V in this case). STRAIN (see last month's constructional article for It will be seen that it is necessary to RELIEF further guidance). It is recommended that join neighbouring triplets together in C5 CLIP you use a 20-way narrow-type d.i.l. socket places by using short jumper wires, to mount it, although the prototype chip formed from single-core tinned copper ARROWHEAD was soldered directly to the board having wire, or using insulated wire if there is a POLARISING double-checked its position first. likelihood of neighbouring wires touch- (BUMP Use another type "B" board and solder ing each other. Usually, solid-core tinned the 20-way header into position, checking copper wire can be formed into shape again for polarity, see Fig.6. Continue with with pliers, often obviating the need for the 10-l.e.d. bargraph array - pin I is an- insulation. Wiring should be effective but notated with a dot or other marking and doesn't need to look very tidy - you will correct polarity is important. be doing quite a lot of prototyping like The s.i.l. resistor (R2) should be this in the future! polarised as before, with pin 1 being Use solid-core jumper wires to intercon- denoted by a spot on the body. A series of nect all the components as shown. The short jumper wires is needed to hook numbering pattern for the 20-way connec- Fig.4. IDC connector assembly. together the components, and these can tor is also given, and jumper wires are again be formed from short pieces of used to link the components to the input orientated as per Fig.4. Cut the ribbon tinned-copper wire. lines IPO to IP7 on the connector, as well cable to length (say, six inches - about Then use insulated jumper wires to care- as to -KW and OV power lines. Closely 15cms) with very sharp scissors to make a fully hook over from the integrated circuit inspect the soldering after assembly, look- clean cut. to the corresponding pads adjacent to the ing for short-circuited joints or "dry" (bad Feed the end of the ribbon dhto the 20-way header. Again the solder pads of or unsoldered) joints. connector's "teeth" and press down the the 20-way header are offset in a particular top section just to grip the wire. A strain order and close attention should be paid to IDC CONNECTOR relief clamp is applied to the cable after- the layout used. A 20-way 0 05-inch pitch ribbon cable wards, but because the ribbon is doubled After completion, scrutinise all wiring is used to link the external I/O boards back over the plug and clamped down with very closely and then insert the chip into to the main PhizzyB hardware. This the strain relief, the cable must initially be its socket (if used) looking for a notch or uses an industry-standard IDC (insula- fed into the connector from the opposite dimple to signify pin I (see Fig.2 in last tion displacement connector) to produce direction - see diagram. (If you get it month's constructional article). an extremely reliable connection: instead wrong, don't worry, because IDC connec- of trying to solder to the wires, the tors can usually be prised apart again and PhizzyB CONNECTION wire's insulation is pierced by sharp metal remade.) In order to use the I/O boards with your "teeth" and an electrical contact is then It takes a surprising amount of pressure PhizzyB, simply hook them to the main made to the conductor within, exactly like to fully squeeze the connector together single-board computer using the two rib- 31V1 "Scotchlok" connectors are used for to pierce the insulation. Don't worry - bon cables. Power up the PhizzyB and car wiring - only infinitely smaller, and the connectors are very accurately made then download the relevant .ram files twenty abreast! and are remarkably strong! The prototype which accompany each demonstration. The IDC connectors used on the leads were tightened together using a small Press the ''Run" button on the PhizzyB prototype were also made by 3M, bench vice, but any improvised method to execute the program, and use the d.i.l. cidentally, but there are plenty of other which applies uniform pressure will be switches to "write" binary numbers to the brands available. (IDC connectors are used suitable. PhizzyB input port, and see what happens universally in modern personal computers, Then double-over the ribbon and push on the l.e.d. display. to interconnect disk drives to the on the strain relief clip to secure every- Move the I/O boards to the other ports motherboard etc.) thing. Repeat the procedure for the other and execute the corresponding programs, in The general orientation of the required end of the cable; you will see that the order to confirm that the I/O ports on your IDC lead is illustrated in Fig.4. Note that: polarising "bumps" on both connectors PhizzyB operate as expected. Be sure to use 1. A "bump" polarises the connector - face the same direction. You should then the relevant .ram program corresponding to this matches a notch in the 20-way header repeat this procedure for a second cable, each I/O port being demonstrated. soldered on the printed circuit boards which is needed for the output board, the If you have any problems, we recom- 2. A tiny arrowhead is moulded into the construction of which is described next. mend that you: IDC connector to indicate pin I • Closely inspect the soldering, look- 3. A red stripe on a (grey) ribbon cable OUTPUT BOARD ing for dry (incomplete) joints, or solder indicates pin I as well. The basic circuit diagram of the L.E.D. bridging adjacent strips on the prototyping So that the interconnection is properly Bargraph Output Board is shown in Fig.5. boards orientated and pin 1 on the input board It contains a dual-in-line integrated circuit • Look for wires soldered into the links to pin 1 on the PhizzyB input port, (a 74LS540 or 74ALS540 octal buffer) wrong locations, especially at the 20-way the notches of the connectors must be which is used as a current amplifier to headers - it is easy to make a mistake OUTPUT PORT 20-WAY CONNECTOR (CON 2) +5V O— 11 10 R2 (SPOT) +5V 2 IRQ 19 N.C. 12 T~ N.C. 9 X 150ft V I ACK 4 N OPO O- 18 N.C. —13 OPO 6 OP1 O- IC1 17 14 BAR1 AAA- OP1 8 OP2 O- 74LS540 10-WAY -W- TO 20 WAY OP3 O- 16 15 LED. OP2 10 CONNECTOR 15 16 BARGRAPH W- OP3 12 CON2 OP4 O- 14 17 AA^ OP4 14 OP5 O- 13 18 AA/^ OPS 15 16 OP6 O- 12 19 A/V^ OPS 17 18 V OP7 O- 11 20 AAA- OP7 19 20 N.C. A/V^ AER1AL VIEW OF PINS OVO- (SPOT) Fig.5. Circuit diagram for the L.E.D. Bargraph Output board, plus 20-way output connector plnout details. 890 Everyday Practical Electronics, December 1998 0T • BUSBAR RESOURCES «) A J *r i* The following items are available i s • [=]• from the EPE PCB Service at the i •— • r ~i« Editorial address (prices including VAT 1C1 • i i* i —• • czm • "B" TYPE and P&P): i •— •i )• BOARD 4-section PhizzyB I/O board £3.95 » •— • CZZ) • Full working version of the PhizzyB fi •— • dZD • fi • CZZD • CD-ROM £14.95 fi —• «l 1* Pre-programmed PhizzyB 19 20 1 (SPOT) CUT microcontroller £14.95 (OPTIONAL) PhizzyB main p.c.b. £14.95 A kit of parts for the PhizzyB I/O cir- cuits described here in Part 2 (includ- "A" TYPE ing the board) is available from Magenta BOARD Electronics. Magenta also supply kits and ready- built units for the main PhizzyB as des- cribed in Part 1: Kit £131.95 inch VAT plus £3 P&P Ready-built £149.99 incl. VAT plus Fig. 6. Component layout and connections for the L.E.D. Bargraph Output board. £3 P&P Note that a "B" section is used. Computer lead £3.99 Plug-top p.s.u. £3.99 PHIZZYB This series is written for those wishing to learn what makes computers really tick. The unique PhizzyB (Physical Beboputer) by Maxfield & Montrose Interactive Inc. combines both software and hardware to interact between the on-screen demonstrations and the advanced practical hardware - the PhizzyB - connected to your PC serial port. Remember that this series is not aimed purely at electronics enthusiasts, but also computer users and others wishing to train in or learn about computer operation. Not a lot of previous electronics experience is required, basically just an ability to solder and recognise components. Even if you have no particular electronics experience, then provided you can solder neatly using a fine-tipped soldering iron, there is an excellent chance that you will be able to solder the hardware together and that it will work first time. Assembled L.E.D. Bargraph Output board. • Inspect for any specks or pieces of HELP! Alvin can be contacted in relation to the swarf, solder or wire offcuts which have Remember that if there are any queries PhizzyB Tutorial. Tell them how they're become stuck amongst the soldering or problems, the authors are on hand doing - they're itching to hear from you! • Try to compare the simple circuit dia- to help. For constructional queries you Next month, we describe how to add a grams against your actual wiring boards can contact Alan Winstanley by E-mail liquid-crystal display to your PhizzyB. • Check for correct orientation of parts ([email protected]) or by post BUZZ THE CHAT ZONE and pin numbers c/o the Editorial address. The EPE Chat Zone on our web site is now • Check the correct program is being You can also check the web site of open s a way for readers to exchange informa- used - open the Simulator assembler and Maxfield & Montrose Interactive Inc. on tion, views, hints and tips in virtually real time. re-assemble if necessary. http://www.maxmon.com where Max and http;//www.epemag.wimborne.co.uk/wwwboard Mmr Assembled switch input board connected to PhizzyB. Assembled l.e.d. output board connected to PhizzyB. Everyday Practical Electronics, December 1998 891 Everyday Practical Electronics are pleased to be able to offer all readers these ELECTRONICS CO-ROMS ELECTRONIC DIGITAL ELECTRONICS TWO CIRCUITS & by Mike Tooley APPLICATIONS COMPONENTS Digital Electronics builds on the knowledge of logic gates ON ONE + THE PARTS covered in Electronic Circuits & Components, and takes CD-ROM users through the subject of digital electronics up to the GALLERY operation and architecture of microprocessors. The virtual by Mike Tooley laboratories allow users to operate many circuits on screen. ELECTRONIC CIRCUITS & COMPONENTS Electronic Circuits & Components "-*41 / Fundatnaituls X17 Digital Fundamuttnls j , ..u.... provides an introduction to the FUNDAMENTALS principles and application of the m Fundamentals introduces the l ■ a V. fx. «■> basics of digital electronics most common types of electronic \ i i !SL f components and shows how they including binary and hexadecimal • 'Ftrr.:. it1 i numbering systems, ASCII, basic are used to form complete circuits. logic gates and their operation, . The virtual laboratories, worked monostable action and circuits, and examples and pre-designed circuits ■— bistables - including JK and D-type allow students to learn, experiment —' 1 and check their understanding as . IT,'Tn- T21 IT.'TUT" flip-flops 0-Ir Si they proceed through the sections i.—' ! e——» : ™ •i-I-! COMBINATIONAL on the CD-ROM. Sections on the iiSl-al l-l •"» risl- ' lw>>l 1^1 disk include; Virtual laboratory - sinusoids Virtual laboratory - flip-flops LOGIC Fundamentals: units & multiples, Multiple gate circuits, equivalent electricity, electric circuits, Semicmdnctor* 4-j.^ Digital Systcim logic functions and specialised logic alternating circuits. functions such as majority vote, Passive Components: resistors, parity checker, scrambler, half and capacitors, inductors, transformers. full adders. Includes fully interactive Semiconductors: diodes, virtual laboratories for all circuits transistors, op.amps, logic gates. Passive Circuits SEQUENTIAL LOGIC Active Circuits Introduces sequential logic Orel including clocks and clock circuitry, THE PARTS GALLERY counters, binary coded decimal and Many students have a good riF-Ti-—-Pi' -I shift registers. understanding of electronic theory Logic laboratory Virtual laboratory - traffic lights but still have difficulty in recognising DIGITAL SYSTEMS the vast number of different types of -*4.1.? Circvits f y fiTi— Manpracmnr wwrtiwi A/D and D/A converters and their electronic components and symbols. r parameters, traffic light controllers, The Parts Gallery helps overcome memories and microprocessors - this problem; it will help students to architecture, bus systems and their recognise common electronic arithmetic logic unit. components and their corresponding symbols in circuit diagrams. jr'^.T'TTriv GALLERY Selections on the disk include: A catalogue of commonly used IC Components mm i--'' ' ? schematics taken from the 74xx Components Quiz and 40xx series. Also includes Symbols 1 111 Tffff It'll photographs of common digital O 1 r [f Symbols Quiz i--l "—l--Ivy HI |ac| integrated circuits and circuit Circuit Technology Circuit technology screen Microprocessor technology. Hobbyist/Student £34 inc VAT Hobbyist/Student £45 inc VAT Institutional (Schools/HE/FE/lndustry) £89 plus VAT Institutional (Schools/HE/FE Industry) £99 plus VAT Institutional 10 user (Network Licence) £169 plus VAT Institutional 10 user (Network Licence) £199 plus VAT MODULAR CIRCUIT DESIGN by Max Horsey and Philip Clayton This CD-ROM has been developed from Max Horsey's Teach-in series designing your circuit A Guide to Modular Circuit Design (EPE Nov "95 to Aug '96). This highly simjiply select your modules from the wide choice available, acclaimed series presented a range of tried and tested analogue and readd how they work and join them up to make your circuit digital circuit modules, together with the knowledge to use and interface them. Thus allowing anyone with a basic understanding of circuit symbols to design and build their own projects. T Essential information for anyone undertaking GCSE or "A" level elec- tronics or technology and for hobbists who want to get to grips with project design. I Over seventy different Input, Processor and Output modifies are LDR L illustrated and fully described together with detailed information on con- struction, fault finding and components, including circuit symbols, pinouts, power supplies, decoupling etc. A full contents list and alphabetical index pin 7 and are provided and, at every stage, alternative modules are offered. 100K j unused pins Written by a highly experienced author and teacher (Max is Head L of Electronics at Radley College), this CD brings it all together for all students of electronics. input processor output "I found that I could design a circuit without my teacher's help. And it worked! Single User Version £19.95 inc. VAT Everything was to hand - which chips to use - and which pins did what." Multiple User Version £34 plus VAT A Web Browser is required for Modular Circuit Design - one is provided on the EPE CD-ROM No. 1 (see opposite) but most modern computers are supplied with one. Interested in programming PIC microcontrollers? iSSfk PICtutor by John Becker Developed from our famous and incredibly popular EPE PIC Tutorial series by John Becker (EPE March to May '98) this CD-ROM, to- gether with the PICtutor experimental and development board, will NOP teach you how to use PIC microcontrollers with special emphasis on 002 NOP 003 NOP 00 iNi>y oo the PICx84 devices. The board will also act as a development lest 004 GOTO Beset: 01 N/A 00 bed and programmer for future projects as your programming skills 005 Besec: NOP 02 PCL 00 006 NOP 03 STATUS 00 develop. 007 NOP 04 FSB 00 This interactive presentation uses the specially developed Virtual 008 05 POBTA 02 PIC simulator to show exactly what is happening as you run, or step 009 06 POPTB 00 OOA HOP ♦ through, a program. In this way the CD brings the EPE PIC Tutorial iijur. series to life and provides the easiest and best ever introduction to the subject. ■ i m Nearly 40 tutorials cover almost every aspect of PIC programming in an easy to follow logical sequence. HARDWARE ■ GSPllg Whilst the CD-ROM can be used on its own, the physical demonstra- rMn Uf tion provided by the PICtutor Development Kit, plus the ability to program and test your own PIC16x84s, really reinforces the les- sons learned. The hardware will also be an invaluable development and programming tool for future work once you have mastered PIC software writing. The virtual PIC Two levels of PICtutor hardware are available - Standard and Deluxe. The Standard unit comes with a battery holder, a reduced number of switches and no displays. This version will allow users to complete 25 of the 39 Tutorials - it can be upgraded to Deluxe at a later date, by adding components, if required. The Deluxe Development Kit is supplied with a plug-top power supply (the Export Version has a battery holder), all switches for both PIC ports plus l.c.d. and 4-digit 7-segment l.e.d. displays. It allows users to program and control all functions and both ports of the PIC and to follow the 39 tutorials on the CD-ROM. All hardware is supplied fully built and tested and includes a PIC16F84 electrically erasable programmable microcontroller. CD-ROM Hobbyist/Student £45 inc. 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CD-ROM ORDER FORM ORDERING Please send me: Version required: ALL PRICES INCLUDE UK □ Electronic Circuits & Components + The Parts Gallery □ Hobbyist/Student POSTAGE □ Digital Electronics □ Institutional □ PICtutor □ Institutional 10 user Student/Single User/Standard Version - price includes postage to most countries □ PICtutor Development Kit - Standard in the world □ Deluxe Export EU residents outside the UK add £5 for j PICtutor Development Kit - Deluxe airmail postage per order □ Modular Circuit Design - Single User OVERSEAS ORDERS: Institutional, 1 Modular Circuit Design - Multiple User Multiple User and Deluxe Versions - overseas readers add £5 to the basic Full name: price of each order for airmail postage (do not add VAT unless you live in an Address;... EU country, then add T7V2% VAT or provide your official VAT registration number). Post code: Tel. 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Measures 22mm x 22m, including mic. 6V-12V operation, 1500m range. £15.45 STLX High-performance Telephone Transmitter VT500 High-power Room Transmitter High performance transmitter with buffered output stage providing excellent stability Powerful 250mW output providing excellent range and performance. and performance. Connects to line (anywhere) and switches on and off with phone Size 20mm x 40mm. 9V-12V operation. 3000m range £16.45 use. All conversations transmitted. Powered from line. VXT Voice-Activated Transmitter Size 22mm x 22mm. 1500m range £16.45 Triggers only when sounds are detected. Very low standby current. Variable sensitivity TKX900 Signalling/Tracking Transmitter and delay with LED indicator. Size 20mm x 67mm. 9V operation, 1000m range. £19.45 Transmits a continuous stream of audio pulses with variable tone and rate. Ideal for HVX400 Mains Powered Room Transmitter signalling or tracking purposes. High power output giving range up to 3000m. Connects directly to 240V A.C. supply for long-term monitoring. Size 25mm x 63mm. 9V operation £22.95 Size 30mm x 35mm. 500m range £19.45 CD400 Pocket Bug Detector/Locator SCRX Subcarrier Scrambled Room Transmitter LED and piezo bleeper pulse slowly, rate of pulse and pitch of tone increase as you Scrambled output from this transmitter cannot be monitored without the SCDM decoder approach signal. Gain control allows pinpointing of source. connected to the receiver. Size 20mm x 67mm. 9V operation. 1000m range £22,95 Size 45mm x 54mm. 9V operation £30.95 SCLX Subcarrier Telephone Transmitter CD600 Professional Bug Detector/Locator Connects to telephone line anywhere, requires no batteries. Output scrambled so Multicolour readout of signal strength with variable rate bleeper and variable sensitivity requires SCDM connected to receiver. Size 32mm x 37mm. 1000m range £23.95 used to detect and locate hidden transmitters. Switch to AUDIO CONFORM mode to distinguish between localised bug transmission and normal legitimate signals such as SCDM Subcarrier Decoder Unit for SCRX pagers, cellular, taxis etc. Size 70mm x 100mm. 9V operation £50.95 Connects to receiver earphone socket and provides decoded audio output to headphones. Size 32mm x 70mm. 9V-12V operation £22.95 QTX180 Crystal Controlled Room Transmitter ATR2 Micro-Size Telephone Recording Interface Narrow band FM transmitter for the ultimate in privacy. Operates on 180MHz and Connects between telephone line (anywhere) and cassette recorder. Switches tape requires the use of a scanner receiver or our QRX180 kit (see catalogue). automatically as phone is used. All conversations recorded. Size 16mm x 32mm. Size 20mm x 67mm. 9V operation. 1000m range £40.95 Powered from line £13.45 QLX180 Crystal Controlled Telephone Transmitter As per QTX180 but connects to telephone line to monitor both sides of conversations. ■ 20mm x 67mm. 9 V operation. 1000m range £40.95 ★ ★★ ★★★ QSX180 Line Powered Crystal Controlled Phone Transmitter Specials As per QLX180 but draws power requirements from line. No batteries required. DLTX/DLRX Radio Control Switch Size 32mm x 37mm. Range 500m £35.95 Remote control anything around your home or garden, outside lights, QRX 180 Crystal Controlled FM Receiver alarms, paging system etc. System consists of a small VHP transmitter with digital encoder and receiver unit with decoder and relay output, momentary For monitoring any of the 'Q' range transmitters. High sensitivity unit. All RF section or alternate, 8-way d.i.l. switches on both boards set your own unique supplied as pre-buill and aligned module ready to connect on board so no difficulty security code. TX size 45mm x 45mm. RX size 35mmx 90mm. Both 9V setting up. Output to headphones. 60mm x 75mm. 9V operation £60.95 operation. Range up to 200m. Complete System (2 kits) £50.95 A build-up service is available on all our kits if required. Individual Transmitter DLTX £19.95 Individual Receiver DLRX £37.95 UK customers please send cheques, POs or registered cash. Please add MBX-1 Hi-Fi Micro Broadcaster £2.00 per order for P&P. Goods despatched ASAP allowing for cheque Not technically a surveillance device but a great Idea! Connects to the clearance. Overseas customers send Sterling Bank Draft and add £5.00 headphone output of your Hi-Fi, tape or CD and transmits Hi-Fi quality to a per order for shipment. Credit card orders welcomed on 01827 714476. nearby radio. Listen to your farvourite music anywhere around the house, garden, in the bath or in the garage and you don't have to put up with the OUR LATEST CATALOGUE CONTAINING MANY MORE DJ's choice and boring waffle. NEW SURVEILLANCE KITS NOW AVAILABLE. SEND TWO Size 27mm x 60mm. 9V operation. 250m range £20.95 FIRST CLASS STAMPS OR OVERSEAS SEND TWO IRCS. Dept. EE SUMA The Workshops, 95 Main Road, Baxterley, Near Atherstone, Tel/Fax: DESIGNS Warwickshire CV9 2LE VISITORS STRICTLY BY APPOINTMENT ONLY 01827 714476 894 Everyday Practical Electronics, December 1998 atu J i * — 1 • rj • ■ d • ri im Ingenuity i N.U .IK unlimited Our regular round-up of readers' own circuits. We pay between £10 and £50 for all material published, depending on length and technical merit. We're looking for novel applications and circuit tips, not simply mechanical or electrical ideas. Ideas must be the reader's own work and WIN A PICO PC BASED not have been submitted for publication elsewhere. The OSCILLOSCOPE circuits shown have NOT been proven by us. Ingenuity • 50MSPS Dual Channel Storage Unlimited is open to ALL abilities, but items for Oscilloscope • 25MHz Spectrum Analyser consideration in this column should preferably be typed or • Multimeter • Frequency Meter word-processed, with a brief circuit description (between • Signal Generator 100 and 500 words maximum) and full circuit diagram If you have a novel circuit idea which would be i': showing all relevant component values. Please draw all of use to other readers then a Pico Technology circuit schematics as clearly as possible. PC based oscilloscope could be yours. Every six months, Pico Technology will be Send your circuit ideas to: Alan Winstanley, Ingenuity awarding an ADC200-50 digital storage Unlimited, Wimborne Publishing Ltd., Allen House, East oscilloscope for the best IU submission. In Borough, Wimborne, Dorset BH21 1PF. addition, two single channel ADC-40s will be They could earn you some real cash and a prize! presented to the runners up. Hot Wire Anemometer - The principle of the hot wire wind- speed indicator (anemometer) depends on an object, much hotter than its ambient LM317IC1 surroundings, being cooled by an amount proportional to the wind speed. Here are two VR1 simple methods by which this principle can be utilised. The circuit diagram shown in Fig. I a uses a C2lOOnl I self-compensating bridge circuit containing 470!! 470!! an op.amp IC1 and an NTC thermistor RTHl TR1 (5k @ 250C). On power-up, the op.amp out- BC107 6 o put goes high, which drives transistor TR1 ca-.'-: (an emitter follower) to feed more current into the bridge circuit comprising resistors Rl, R3 and R4 and the thermistor. ?TM1 Fig. lb. Anemometer formed from a With the values given, the thermistor self- variable regulator. heats until the value drops to 1 kilohm (at around 650C) when it equals resistor R4 in Rl1 value. Equilibrium is then established, so that INPUT FROM / 00k REGULATOR O— \A/>—iv v the circuit supplies sufficient current to the (FIG.Ib) thermistor to match heat losses through con- Fig. la. "Hot- wire" principle duction or convection currents around the Anemometer circuit. device. If the thermistor (RTHl) is exposed to air a voltage across it of around 12V and a ME1 flow, this results in a proportional increase in current of 12mA. Hence preset VR1 should 100MAU^ (nAry the op.amp output voltage which will try to be set to just under 100 ohms in value. The VR210k maintain the state of equilibrium. In order to regulator output is 13V in still air and rises compensate for low ambient temperatures, a markedly when the thermistor is exposed to 0V i second thermistor (shielded from the wind), airflow. could be arranged to offer a small voltage A method of displaying the output on a Fig. 1c. Moving coit meter display for output of appropriate polarity. microammeter is shown in Fig. 1c, and it is the Anemometer of Fig. lb. How an LM3I7 variable regulator, IC1, also a good idea to decouple the "still air" could be used in an alternative design is quiescent voltage at the same time. This the meter only registers the "excess" voltage shown in Fig.lb. To self-heat the thermistor "still air voltage" could be nulled out from developed by the airflow. in still air so that its resistance is Ik requires the current by using a — 15V supply, so that A.E. Whittaker, Stone, Staffs. formula Rl = 1000/P ohms, where P is the Soldering Iron "Ready" Indicator - I(0)K power of the iron. This ensures about 15mA The simple circuit of Fig. 2 is suitable for r.m.s. runs through the I.e.d. when the iron is D1 indicating when your soldering iron has R2 L.E D. warming up. For R1 = 22 ohms and an iron of reached its operating temperature. It may be 100!! RED 45W, a normal 0-6W resistor is fine. used in conjunction with any thermostatic A Resistor power dissipation is given by the for- Rl w iron such as the Weller TCP series, and it can 22!! mula: even be used with thermostatic irons that -o R\ use a low voltage power supply, and also MAINS D2 MAINS Ht'< r; f INPUT 5V6 OUTPUT electronically controlled irons. 400mW TO IRON The circuit is connected in series with the -M— watts, where PI is the iron power and Vs is the mains supply to the soldering iron. The I.e.d. Dl mains r.m.s. voltage. will illuminate when the iron is drawing enough Fig. 2. Circuit diagram for the Solder- The circuit must be constructed within a fully current to drop a few volts across resistor Rl. ing iron Ready indicator. (See text for insulated plastic box and care must be taken This means that when the thermostat in the iron to ensure than no metal mounting screws etc. switches off, the I.e.d. will extinguish to indicate component ratings.) which are accessible to the user can become that the iron is ready. The Zener diode D2 With the values shown, load powers of be- live. Use nylon mounting screws, protects the I.e.d. against reverse voltages and tween 45W and 60W are suitable. For other Jeremy Siddons, limits the forward voltage to 5-6V. powers, resistor Rl is adjusted according to the Buxlon, Derbyshire. Everyday Practical Electronics. December 1998 895 Lossless Current Sensing - BYV133 Fig.3. Lossless Centre-tapped dual rectifiers instead of full-wave bridges are still used 15V H current sensing in some applications despite the poorer transformer utilisation and o oO for centre-tap efficiency of the circuit. A simple way in which to sense the output current o o transformer. of this type of power supply, without the need to resort to "lossy" shunts o o o or expensive Hall-effect devices, is shown in circuit diagram Fig.3. 230V a.c O A centre-tap rectifier draws d.c. current from each transformer secon- o dary winding, whilst the primary current is alternating. This d.c. current o o BYV133 corresponds to the average d.c. current and causes a voltage drop in the N O 15V copper windings which can be measured. In Fig. 3, the winding resistance ►I 02 is actually used as a shunt resistor for the ammeter, so the apparent amp 1000n^S tk. D.c. OUTPUT reading will increase with winding temperature by some 25 per cent. e a 25V Point "X" yields a negative d.c. voltage which is proportional to cur- rent taken from the d.c. output terminals. Resistors Rl and R2 should If/in preferably be matched values to resolve low currents, though the test circuit used 5 per cent resistors and detected currents from 60mA up to 8A, which was the limit of the transformer. c: Gerard la Kooy, Mew Zealand. Foghorn Timing Switch - The circuit illustrated in Fig. 4 was common to all four patterns. It bypasses the no purpose. Eventually C2 discharges to 1/3 of designed to sound a foghorn signal every switching system and is easily followed. the supply and 1C2 output goes high. This two minutes as laid down in Rule 35 of the Operation revolves around the action of clocks the 4017 and QI goes high. Inlernalional Regulations for Preventing capacitor C2 and IC2. The potential across Switch SI is set to position "1", then Q1 Collisions at Sea. 1972, and includes the C2 alternates between 1/3 and 2/3 of the 12V output is diverted straight through via diode following four signals: supply. Pin 3 of the 555 switches high and D2 and resistor R2, to turn on transistor TR2. 1. Power vessel under way. low alternately, driving the boat's foghorn Thus the output transistor TRI is inhibited by 2. Power vessel stopped. relay via transistor TR1. and also feeding shunting its base to 0V, and this principle is 3. Sailing, fishing, towing, etc. back pulses to clock the 4017 chip. repeated for the rest of the outputs via the 4. Vessel being towed. The first four outputs Q0-Q3 of this decade various switch contacts and diodes, although Rule 35 does not apply to vessels less than counter (ICI) provide the "dashes and dots" the 555 continues timing and resetting. 12 metres in length, although it does say, "if and the remainder provide the delay of two The rotary switch S1 can be moved to any she does not, she shall make some other effi- minutes before ICI is reset by the final count of four positions to generate a sequence of cient sound signal at intervals of not more than on pin 11, after which the cycle repeats. At foghorn blasts automatically. Switch S2 may two minutes." switch-on, capacitor C2 is fully discharged, be pressed to sound the horn manually. The circuit idea consists of a l-of-10 so pin 3 of the timer IC2 goes high and the Calibration is best carried out in position counter (IC1) clocked by a 555 (IC2). horn sounds. Also at switch-on, a positive- "4", with control VR3 set quite low. Set Steering diodes are used on appropriate pulse is applied through capacitor C1 to reset VR2 for a fairly long blast, followed by VR4 outputs of the 4017 counter ICI and are ICI at pin 15, so pin 3 of ICI is now high. to VR6 for short blasts. selected using a system of rotary switches to This "high" on Q0 (pin 3) starts to charge Next, select position "2" and adjust VR1 operate a transistor-driven relay. This in turn capacitor C2 via diode D1. potentiometer VR2, to lengthen the second dash, to match the first controls the foghorn, which sounds the and diode DI3 which allows the positive charg- original long blast. Adjust VR7 for the in- corresponding number of blasts. ing current to bypass VR7, whose function is to terval between sounds, and finally VR3 to vary the spaces between the signal blasts. Even- pad out the two minute interval. (So that you Circuit Operation tually, in a time constant set by the combination avoid incurring the wrath offellow mariners, Consider the circuit operation with the of VR2 and C2. the timer output, 1C2 pin 3, or at least alarming everyone. I suggest test- rotary 4-way 3-pole switch set at position goes low, and C2 starts to discharge through ing is performed using a 12V buzzer! A.R.W.) "1". This generates a "dash" which is VR7. Output Q0 of ICI is still high but serving Don Clark, Seaford, East Sussex. -O +12V ** I D1 014 1N4148 1N4148 C -*+T- -wv RLA1 | MANUAL| 010 VR4 1N4148 470k —vVV ^►hrVW-j- 16 □ VCC qo u 02 O 2 TR1 K ^ 1N4148 Sla o R3 2N3053 Q1 R 10k C1 ■1 a k ST VCC 10n IC1 Q2 4 VR5 OUT -^-w- 4017 Q3 f Q* I1 011 470k 04 05 ^ 1N4148 HORN T 1N4148 VW-j- IC2 Q5 -rHr- 555 DISCH 06 06 03 07 1N4148 1N4148 TRIG, £ 08 —N- -rWr VR6 13 T 09 07 D12 470k VR7 1N4148 1N4148 470k GND CO 1 -T*h- T^hr-WVj- -vW- 08 D 1N4148 04 1N4148 013 09 —W- 1N4148 1N4148 VR3 -M- 2M2 -H4- —AV C2 C±D TR2 R2 1 BC183 47k 10M -w- -o ov Fig. 4. Circuit diagram for a Foghorn Timing Switch. 896 Everyday Practical Electronics. December 1998 BATTERY MOTOR WITH GEARBOX. Will operate on any DC GLISTENING JEWEL CHRISTMAS LIGHTS. This is a 40 light set TOROIDAL MAINS TRANSFORMERS voltage between 6V and 24V, price £3. Order Ref: 3P108. A which is twice the normal so you will have a tree to be really envied. All with 220/240V primary winding If you put these around the door or window, it will please everybody speed controller is available for this. £12 in kit form or £20 They are all ready with 2 spare bulbs, price £4,50. Order Ref: 4 5P2 24V + 24V at 25VA would made up. but if you intend to operate it from the mains, then 35mm PANORAMIC CAMERA. Has super wide lens, ideal for give 25V at 1A or 50V at our power supply 2P3 will give you 3 speeds and will also holiday viewing, is focus free and has an extra bright and clear reverse. Price of power supply is £2. viewfmder Brand new and guaranteed, individually boxed, £6.50. VzA, price, £3. Order Ref: ANOTHER PROJECT CASE. Should be very suitable for a Order Ref 6 5P2 3P245. non-recognisable bug or similar hand-held device. It is 150mm FLASHING BEACON. Ideal for putting on a van, a tractor or any 30V + 30V at 120VA would long. 36mm wide and 15mm thick. Originally these were TV vehicle that should always be seen. Uses a Xenon tube and has an remote controls, price 2 for £1. Order Ref; 1068. amber coloured dome Separate fixing base is included so unit can give 30V at 4A or 60V at 2A, A MUCH LARGER PROJECT BOX. Size 216mm x be put away if desirable Price £5 Order Ref 5P267 price £8. Order Ref: 8PG2. 130mm x 85mm with lid and 4 screws. This is an ABS box MEDICINE CUPBOARD ALARM. Or it could be used to warn when 110V + 110V at 120VA which normally retails at around £6. All brand new. price £2.50. any cupboard door is opened The light shining on the unit makes the bell ring. Completely built and neatly cased, requires only a battery. would give 110V at just over Order Ref: 2.5P28. £3 Order Ref 3P155 8A or 220V at VfeA, price £8. Order Ref: 8PG3. BT TELEPHONE EXTENSION WIRE. This is proper heavy WATER LEVEL ALARM. Be it bath, sink, cellar, sump or any other 35V + 35V at 150VA would give 35V at 6V2A or 70V duty cable for running around the skirting board when you thing that could flood. This device will tell you when the water has want to make a permanent extension. Four cores properly risen to the preset level Adjustable over quite a useful range. Neatly at 2A, price £8. Order Ref: 8PG9. colour coded. 25m length only £1. Order Ref: 1067. cased for wall mounting, ready to work when battery fitted, £3. Order 35V + 35V at 220VA would give 35V at SVaA or 70V LARGE TYPE MICROSWITCH. With 2in. lever, changeover Ref 3P156 at SViA. price £9. Order Ref; 9PG4. contacts rated at 15A at 250V, 2 for £1. Order Ref: 1/21R7. BIKE RADIO. In fact, it's more than a radio, it's an alarm and a MINI MICROSWITCH. Only approximately 15mm long with a spotlight. The radio is battery operated, of course, and needs 3 AA 110V + 110V at 220VA would give 110V at 2A or 20mm lever which could quite easily be removed, changeover cells. Only one band but this is the FM band so will receive Radio 1 220V at 1 A, price £10. Order Ref: 10PG5. contacts rated at 5A AC, 50p each. Order Ref: 1/21R8. and 2 Comes complete with handlebar fixing clips. Price £4 Order 45V + 45V at 500VA would give 45V at 11A or 90V at FLEX PROTECTORS. Rubber. 30mm long, 8mm diameter Ref: 4P72. PLAY THAT TUNE. Hand-held Rainbow Piano'. Driven by 2 AA 5V2A, price £20. Order Ref: 20PG7. with a 12mm shoulder. Ideal for protecting flex passing through batteries. Has 22 playing keys and 2 others, one for rhythm and one 110V + 110V at 500VA would give 110V at 5A or a metal panel. 5 for £1. Order Ref; 1/21R10. tor tempo. A beautifully made little unit, comes complete with the 220V at nearly 3A, price £25. Order Ref: 25PG8. 10K POT. With double-pole mains on/off switch, good length piano songcard which shows the user which buttons to press for of Viin. spindle and hex fixing nut. 50p each. Order Ref: London Bridge'. Happy Birthday to You'. Jingle Bells' and other 1/22R6. tunes. An ideal slocking filler that any child will be delighted with. SUPER WOOFERS. DITTO but 5K. Order Ref: 1/11R24 Price £3. Order Ref:3P101B A 10in. 4ohm with power AMSTRAD POWER SUPPLY AMPLIFIER. This is quite a big BUMP "N GO SPACESHIP. A wonderful present for a budding rating of 250W music and unit, measures approximately 8in. long and S'/an. wide and young electrician It responds to claps and shouts and should it strike has a heatsink approximately 3in. high. At one end is the an object, it will set off in another direction. Kit contains all the parts normal 150W. Normal sell- mains transformer which looks to be about 40VA. Then there and a youngster should be able to assemble but you might have to ing price for this is is an assortment of i.c.s. power transistors and the lead com- help with the soldering of the components onto the p.c.b. The £55 +VAT. you can buy at assembly instructions are very detailed and explicit and providing he ing out terminates on a panel with twin speaker sockets and follows the step by step illustrations then a successful spaceship will £29 including VAT and miscellaneous input sockets. Price £5. Order Ref: 1/1R2. result price £9 Order Ref: 9P9 carriage. Order Ref; 29P7. BALANCE ASSEMBLY KITS. Japanese made, when as- PHILIPS 9in. MONITOR. Not cased, but it is in a frame for rack The second one is an Sin. sembled ideal for chemical experiments, complete with mounting, it is high resolution and was made to work with the IBM tweezers and 6 weights 0-5 to 5 grams. Price £2. Order Ref; One per disk computer. Price £15. Order Ref: 15P1 4ohm. 200W music. 200W normal, again by 2P444. METAL CASE FOR 9in. MONITOR. Supplied as a flat pack, price Challenger, price £18. Order Ref: 18P9. SUPER CROMPTON PARKINSON MAINS MOTOR. Really £12 Order Ref 12P3 Deduct 10% from these prices if you order in pairs well made, totally enclosed by ventilated framework. Size3 ap- TELEPHONE EXTENSION LEAD. Nicely made and BT approved. proximately 4in. diameter, 4in. high and with 2in. of a sin. Has the plug into BT socket one end and the telephone socket the or can collect. These are all brand new in maker's spindle. Speed is 750rpm, hp is not quoted but we estimate other end, total length 12m, £2. Order Ref: 2P338 packing. this to be around 1/6hp. Price £10. Order Ref: 10P149. ORGAN MASTER KEYBOARD. Three octave keyboard, extremely EQUIPMENT COOLING BLOWER. Near enough Sin. square well made and with piano size keys. New and unused, only £5 Order Ref: 5P282. SMART HIGH QUALITY and 1 Vain, thick but a really good air mover. Mains operated, INSULATION TESTER WITH MULTIMETER. Internally generates price £4 Order Ref: 715L. voltages which enable you to read insulation directly in megohms ELECTRONIC KITS OVEN THERMOSTAT with knob calibrated so you can set it to The multimeter has (our ranges, AC/DC volts. 3 ranges DC mil- All kits are complete with p.c.b. and other cut out at any temperature up to 600 F, £3. Order Ref: 3P229. liamps, 3 ranges resistance and 5 amp range. Ex-British Telecom components in a blister pack SPEAKER IN CABINET. Just right if you want music in but in very good condition, tested and guaranteed, probably cost at the garden. Cabinet size approximately Sin. x5in. x4in. thick, least £50 each, yours for only £7.50 with leads, carrying case £2 CAT. NO. DESCRIPTION £ speaker is 6Vain. 8 ohm. These are ex-equipment but in tip lop extra. Order Ref: 7 5P4 condition, price £4 each or 2 for £7. Order Ref: 812L. REPAIRABLE METERS. We have some of the above testers but 1003 5W electronic siren 2.53 PURE SINE WAVE GENERATOR. All parts to make this. £3. faulty, not working on all ranges, should be repairable, we supply 1005 Touch switch 2.87 Order Ref. 1/1 OR 14. diagram. £3. Order Ref: 3P176. 1008 SF function generator . 6.90 LCD MULTIRANGE VOLTMETER AMMETER. A high quality S'/st DOORBELL PSU. This has A C. voltage output so is ideal for digit Le d. panel meter, incorporating an A-D converter chip (7106) 1010 5-input stereo mixer with monitor operating most doorbells. The unit is totally enclosed so per- to provide 5 voltage ranges and 5 current ranges within one unit. output 19.31 fectly safe and it plugs into a 13A socket. Price only £1. Order Ranges are selected by onboard connectors and expandable by 1016 Loudspeaker protection unit 3.22 Ref: 1/30R1. resistors. Price £11.50. Order Ref: 11 5P2. PIANO ON KEY CHAIN. Although it is quite small, only 20mm long, 1017 30W linear CB 14.71 THIS MONTH S TWO FOR ONE OFFER IS it will play any tune Instructions with it tell you which keys to press 1020 0-50 minute timer 2.99 THE SWITCH MODE POWER SUPPLY tor Happy Birthday'. Twinkle Twinkle Little Star'. Jingle Bells' and 1023 Dynamic head preamp 2.50 London Bridge'. It is also a light, it has a little lamp which can be Made by Astec, outputs are 12V at 4A and 5V operated by the end switch. Battery operated (not included), price 1024 Microphone preamplifier 2.07 at ISA. This PSU can be modified with a few £1 50 Order Ref: 1.5P39. 1025 7W hi-fi power amplifier 2.53 extra components and would then give 12V at 12V RECHARGEABLE YUASA BATTERY. Sealed so usable in any Running lights position - suit golf trolley, lawn mower, portable lights, etc.. etc., only 1026 4.60 10A d.c. We give the details. The price is still £3 50 Order Ref:3.5Pl1. 1027 NiCad battery charger 3.91 £9.50 but you get two instead of one. CHARGER FOR YUASA BATTERY. This battery charger plugs into 1030 Light dimmer 2.53 Offer ends 31st December. Order Ref; 9.5P4. a 13A socket, charoes at approximately 1/2A so it would charge this battery overnight. Complete with croc clips, ready to go, £5. Order 1032 Stereo tone control 4.14 Ref; 5P269. 1039 Stereo VU meter 4.60 GEAR WHEELS. Set of 5. quite small, should enable you to QUARTZ CLOCK MOVEMENT. A quality made movement with 1042 A.F. generator 350Hz-16kHz 1.70 get a variety of speeds, mounted in a metal case but easy to quartz crystal accuracy. Requires only one AA battery which will remove and use separately. Price £1 the set. Order Ref: D409. keep it going for 2 years or more. It is self-starting and maintenance- 1043 Loudness stereo unit 3.22 WIND GENERATORS. The ex-OPO alternator, our ref 5P249. free An extremely reliable unit. Universally applicable and easy to 1047 Sound switch 5.29 has been used to generate from the wind. We understand mount with centre fixing. Ideal if you want to give someone a special 1048 Electronic thermostat 3.68 present of a picture with a clock. Complete with a set of hands. Price it will light a 100W bulb or through rectifiers would charge £3. Order Ref:3P111. 1050 3-input hi-fi stereo preamplifier 12.42 batteries. These are ex-GPO equipment but fully guaranteed, 8mm PROJECTORS. With zoom 1052 3-input mono mixer 6.21 price £5 each. lens, brand new and perfect, com- CYCLE LAMP BARGAIN. You can have 100 6V MES bulbs plete with one reel and handbook. 1053 Electronic metronome 3.22 for just £2.50 or 1,000 for £20. They are beautifully made, Regular price over £100. yours for 1054 4-input instrument mixer 2.76 slightly larger than the standard 6-3V pilot bulb so they would £39. Order Ref:39Pl 1056 8V20V 8A stabilised power supply 12.42 be ideal for making displays lor night lights and similar applica- Ditto but with sound as well and a tions. 50 joined in series can be connected to the mains and mike, £49 Order Ref: 49P1. The 1057 Cassette head preamplifier 3.22 would make a very attractive window display. 100 for £2.50. zoom lens alone is worth more. 1059 Telephone amplifier 4.60 Order Ref . 2.5P29. SOLDERING IRON. Super mams powered with long life ceramic 1062 5V 0-5A stabilised supply for TTL 2.30 12Vx12V RELAY. Miniature, clear platic enclosed, has one set element heavy duty 40W (or the extra special job. Complete with 1063 12V 2A power supply 2.30 changeover contacts, one set that breaks contact and 3 sets plated wire stand and 245mm lead. £3. Order Ref: 3P221. that make contact. Price £1 each. Order Ref: GR30. DIGITAL THERMOMETER. Suitable for outdoorsc or indoors, has an 1064 + 12V 0-5A stabilised supply 3.22 COMPONENT MOUNTING PANEL. Heavy Paxolin. size ap extra wide temperature range -50 C to +70 C. Its sensor can be 1067 Stereo VU meter with leads 9.20 proximately lOin x2in. with 32 pairs of brass pillars for solder- outside but with the readout inside. £4. Order Ref: 4P104. 1068 10V 0-5A stabilised power supply 2.53 ing or binding on components. £1. Order Ref: 1/7RC26. DYNAMIC MICROPHONE. 500 ohm, plastic body with black mesh AIR-SPACED TUNING CAPACITOR. Twin lOOpF with trim- head, on/off switch, good length lead and terminated with audio plug, 1070 Hi-Fi preamplifier 7.47 mers, extra small. Fixed from the front by 3 screws, £2 each £2. Order Ref; 2P220. 1071 4-input selector 6.90 Order Ref: 1/7RC29. 1082 Car voltmeter with l.e.d.s 7.36 PEA LAMPS. Very tiny, only 4mm, but 14V at 0 04A. wire- 1083 Video signal amplifier 2.76 ended, 25p each. Order Ref: 1/7RC28. HIGH AMP THYRISTOR. Normal two contacts from the top 1085 D.C. converter 12V to 6V or 7-5V to 9V 2.53 and heavy threaded fixing underneath. We don't know the 1/10th HORSEPOWER 12V MOTOR. Made by Smiths, the body 1086 Music to light for your car 4.60 amperage of this but think it to be at least 25A. Price 50p each. 5length of this is approximately 3in.. the diameter 3in. and the spindle 1093 Windscreen wiper controller 3.68 Order Ref: 1/7RC43. tein. diameter Quite a powerful little motor which revs at 2000rpm. 1094 Home alarm system 12.42 THREE LEVEL PRESSURE SWITCH. All 3 are low pressures Price £6 Order Ref: 6P47. and the switch could be blow-operated. With a suitable tubing MINI BLOW HEATER. IkW, ideal for under desk or airing cupboard, 1098 Digital thermometer, with l e d. 11.50 these switches could control the level of liquid, etc.. price £1 etc Needs only a simple mounting frame, price £5. Order Ref: 5P23. 1100 2x18W interated amplifier 18.39 Order Ref: 67. 1101 Dollar tester 4.60 BREAKDOWN UNIt. Order Ret: BM41001. This is probably TERMS 1106 Thermometer with l.e.d.s 6.90 the most valuable breakdown unit that you have ever been Send cash, PO. cheque or quote credit card number offered. It contains the items specified below, just 2 of which - orders under £25 add £3.50 service charge. 1107 Electronics to help win the Pools 3.68 are currently selling at £3.50 each. Other contents are: 1112 Loudspeaker protection with delay 4.60 Computer grade electrolytics. 330>xF 250V DC. you get 4 of 1113 2x18W power amplifier 5.98 these. 4.700nF at 50V DC. you get 2 of these. I.OOOjlF at 16V 1115 Courtesy light delay 2.07 DC, you get one of these, and 16A 250V double rocker switch. J & N FACTORS 115V to 250V selector switch. You also gel a standard flat pin 1118 Time switch with triac 0-10 mins 4.14. instrument socket, a 250V 5A bridge rectifier. 2x25A bridge Pilgrim Works (Dept. E.E.) 1122 Telephone call relay 3.68 rectifiers mounted on an aluminium heatsink but very easy to Stairbridge Lane, Bolney, 1123 Morse code generator 1.84 remove. 1126 Microphone preamplifier 4.60 2 /VP/V powered transistors ref BUV47. currently listed by Sussex RH17 SPA Maplins at £3.50 each, a power thyristor, Mullard ref. BTW69 or 1127 Microphone tone control 4.60 equivalent, listed at £3. Telephone: 01444 881965 1128a Power flasher 12V d.c. 2.53 All the above parts are very easy to remove, 100s of other parts (Also Fax but phone first) 1133 Stereo Sound-to-Light 5.26 not so easy to remove, all this is yours for £5. Order Ref: 1/11R8. Everyday Practical Electronics, December 1998 897 INTERWmm Robert Penfold - SERIAL L.C.D. REMOTE MONITOR FOR YOUR PC IN THE previous Interface article (Sept article, it is possible to read information New Data '98) we considered the subject of using from the modules, but in normal opera- RS232C serial interfaces do not use "intelligent" liquid crystal display (l.c.d.) tion this is unnecessary. Accordingly, normal 5V logic levels, but instead modules as a simple form of monitor for this l.c.d. interface can write data to the operate with nominal signal voltages of a PC. Interfacing to the PC was via module but it cannot read any status plus and minus 12V. The input signal the "easy route" provided by a parallel information from it. must therefore be processed to produce printer port. Some readers prefer to use The serial to parallel conversion is an output at normal logic levels for the a PC serial port wherever possible be- provided by a 6402 UART (univer- UART. Also, the raw input signal is of cause their PC has a spare serial port, but sal asynchronous receiver/transmitter), the wrong polarity and must be inverted the parallel port or ports are occupied. and in this case only the receiver before it is fed to the UART. A single Serial interfacing also has a potential ad- device is utilized. No connections are transistor inverter stage is all that is vantage in that it can be used with required to provide this signal con- long connecting cables, and in this ditioning. application a simple two-wire link is Counter/ As soon as bytes of data have been all that is needed. This opens up the Latch decoded they are placed onto the 8-bit possibility of using an l.c.d. module output of the UART. This is fine as as a remote monitor for a PC. C-R far as it goes, but the l.c.d. module As explained in previous Interface Delay has no way of knowing when new articles, operating your PC add-ons £1 data is present on the data bus. Each via a serial port is inevitably more time new data is placed on the bus a complex than using a parallel port. RS strobe pulse must be applied to the One reason for this is simply that Input Inverter/ 8-Bit LCD E enable (E) input of the l.c.d. mod- the interface must include parallel-to- Converter Data Bus Module ule. The "data ready" output of the serial and (or) serial-to-parallel con- UART goes high each time new data versions in addition to the main cir- is placed on the outputs, and this flag cuit of your add-on device. can be reset by taking the "data reset There can also be problems with 24576MHz 4-Stage n ready" input of the UART low. a lack of handshake lines. A serial Oscillator Binary Divider In this interface the data "ready port does actually have handshake output" is automatically reset by inputs and outputs, but these only Fig.l. Block diagram for the Serial L.C.D. feeding it from the "data ready reset" provide basic on/off control of the Monitor for your PC. output via an inverter. A simple C-R data flow. Your add-on may require circuit provides a delay that stretches something more than this, and it is often made to the transmitter section of the the output pulse produced at the " data necessary to improvise in order to obtain device. ready" output, and this ensures that it the desired result. Due to the lack of any clock or reliably latches data into the l.c.d. A serial interface is also relatively slow, other timing signals the transmitting and module. but this does not matter in all applica- receiving devices can only be accurately tions, and is of no significance in the synchronized by using standard trans- Short-Comings current context. An ordinary serial inter- mission rates. This interface is designed This still leaves a major short-coming face can transfer one or two kilobytes per to operate at 9600 baud, which means in that two types of data are written to second, which is sufficient to rewrite the that bits are sent at a rate of 9600 bits per the module. Initially two or three bytes display in a fraction of a second. second. of data are written to the module to set it The UART's clock signal is at 16 times to the correct operating mode, and the Perfect Timing the required baud rate, which works out "register select" (RS) input of the mod- The block diagram of Fig.l helps to at 153-6kHz for a baud rate of 9600. This ule must be held low while these in- explain the way in which this serial is provided by a 2-4576MHz crystal os- structions are sent. Then the "register interface for l.c.d. modules functions. cillator and a four stage (divide by 16) select" input is taken high, and further As explained in the previous Interface binary counter circuit. 1-5V R8 R5 C4 34 35 37 38 39 2k2 ikh 2k2 47U ICXi 5 14 XI 6 13 15 16 2.4576MHz 7 12 10 Hoh- IC2 8 11 LC.D. .17 VR1 ICS iC1 9 10 10k 330k 40248E 4017BE R3 TR2 6402 10 9 Module TR3 5k6 BC547 BC549 c 13 TR1 71—yw- 11 6 b BC549 c 12 7 14 8 "TXD A SK1 R7 C5 C2 Input 01 R4 R6 16 18 39k 1 u 33p 27p Gnd Y 1N4148 • Ik 1k6 -O0V Fig. 2. Full circuit diagram for the Serial L.C.D. Monitor for your PC. 898 Everyday Practical Electronics, December 1998 bytes of data are interpreted as character It also takes the "inhibit" input of IC3 ~ Listing 1: L.C.D. Test Program _ information. high so that further pulses at the clock The simple system used in this inter- input have no effect. After the initial 10 REM LCD TEST PROGRAM face has a counter that holds the "register three bytes of data the l.c.d. module 20 SPORT = &H2F8 select" input low for the first three bytes therefore treats all further data as charac- 30 OUT SPORT,48 of data, and holds it high thereafter. This ters to be displayed. 40 GOSUB 130 enables the module to be set up in the required manner, and it can then be fed Power Point 50 OUT SPORT,14 with the relevant data information. Due to the use of CMOS integrated 60 GOSUB 130 There is an obvious flaw in this ar- circuits and a liquid crystal display the 70 OUT SPORT,5 rangement, which does not permit the total current consumption of the circuit is 80 GOSUB 130 module to be set back to the com- typically less than 10mA. There is no 5V 90 INPUTAS mand mode to permit cursor positioning. output available from a PC serial port, 100 A = ASC(A$) Despite this limitation the interface is but methods of obtaining a suitable sup- 102 IF A = 36 THEN GOTO 200 perfectly usable, and it is just a matter of ply from one of the other ports have 110 OUT SPORT,A using the mode of operation that auto- been described in previous articles. If 120 GOTO 90 matically scrolls the display each time it you have a fairly modern PC it might be 130 FOR D = 1 TO 2000 receives a new byte of data. The cur- worthwhile investigating its USB ports, 140 NEXT sor remains stationary and the display as these can provide a 5V supply output. 150 RETURN scrolls to the right, rather than vice versa. The connections to the serial port are 200 FOR C = 1 TO 40 If necessary, with this mode of opera- made via a 9-way or 25-way female 210 OUT SPORT,32 tion the screen can be cleared simply by D-connector, depending on the style of 220 GOSUB 130 writing a series of spaces to the mod- serial port used on your PC. Connec- 230 NEXT C ule so that any existing characters are tion details for both types of port are 240 GOTO 90 scrolled of the end of the display. Admit- provided in Fig. 3. tedly this scrolling method of operation is relatively crude, but it keeps the inter- Software face reasonably simple, and also avoids The interface will only work properly using the interface on serial port 1, a value complications in the software. if the serial port is set for the correct of &H3F8 must be used here instead. baud rate and word format. From The next six lines of the program out- Circuit Details MS-DOS this is achieved using the Mode put three bytes of data to the display, The full circuit diagram for the Serial command. For serial ports one and and these set it to the correct operating L.C.D. Remote Monitor for PC interface two respectively, use the command mode. First a value of 48 sets the display appears in Fig. 2. Transistor TR2 is used "coml:96,n,8,l," or "com2:96,n,8,l,". to single line operation, 8-bit data trans- in the inverter stage at the serial in- fers, and the normal 7x5 font. Then a put, and it operates as a simple common value of 14 switches on the display and emitter switch. The clock oscillator uses selects a visible but non-blinking cursor. TR1 in a conventional crystal oscillator Finally, a value of 5 sets the entry circuit, and 1C1 is the four stage binary mode, and in this case the cursor is set to divider. The 4024BE used for IC1 is ac- stay at the left of the display with the tually a seven-stage divider, but in this O O 6 O 6 on-screen characters scrolling one place circuit only the first four stages are used. \ 6 o o 6 to the right each time a new character is As suggested by the "universal" part of received. A subroutine provides a delay its name, the UART (IC2) can handle any that ensures the data is not written to the normal serial word format. Its control display too quickly. inputs are hard-wired for operation with one start bit, eight data bits, one stop bit, Character Loop The next part of the program is a loop and no parity checking. A long positive ooooooooooooo reset pulse is required at switch on, and that waits for a character to be entered at this is provided by capacitor C4 and >6000000000007 the keybpard, and the RETURN key to be resistor R6. pressed. It then outputs the correspond- The eight data outputs of IC2 connect ing ASCII value to the display, which direct to the corresponding inputs of the should produce the appropriate character l.c.d. module. Potentiometer VR1 is the F/g.3. Connection details for both types immediately to the right of the cursor. contrast control for the display module, of PC serial port. The program loops indefinitely so that it is adjusted for the best display quality. you can enter as many characters as you The easiest way of sending serial data like, but they must only be entered one Data Ready is to write information to the base ad- at a time. The usual CONTROL-BREAK The "data ready" output of IC2 (pin dress of the appropriate serial port. This combination will terminate the program. 19) drives inverter TR3 by way of a is either &H3F8 for serial port one, or Entering a dollar ($) sign causes the simple C-R timing circuit that is com- &H2F8 if you are using serial port two. program to branch to the subprogram at prised of resistor R7 and capacitor C5. As the Serial L.C.D. Remote Monitor for line 200. This loops the program 40 times, The inverted signal at the collector of PC interface does not use any form of writing a space (ASCII value 32) to the TR3 drives the "data ready reset" input handshaking it is necessary to provide a l.c.d. module on each loop, so that the of IC2 (pin 18). hold-off to prevent data from being writ- screen is cleared. As explained previously, this produces ten at an excessive rate. The speed of the There is a minor irritation when using a positive pulse each time fresh data is system is limited by the rate at which the the l.c.d. module in the right scrolling placed on the outputs of IC2. This pulse serial interface can transfer data, and with mode, which is that the text strings have is fed to the "enable" input of the l.c.d. a baud rate of 9600 just over one milli- to be written in reverse order! Thus, module (pin 6) to indicate that new data second is required per byte of data. in order to display "Hello-World" it is is available, and it is also fed to the The accompanying GW-BASIC listing actually "dlroW-olleH" that has to be clock input of IC3 (pin 14). The latter is sets the display module to the correct written to the display. a 4017BE decade counter and one-of-10 mode of operation and then trans- decoder. fers single characters from the The l.c.d. module's RS input (at pin keyboard to the module. Note that 4) is driven from output 4 (pin 10) of the GW-BASIC INPUT function ICS's decoder section, which goes low at will not accept a space as a valid switch-on when IC3 is reset by the same character for a text string, and that Hel reset circuit that is used for the UART. entering a space will terminate the After three bytes of control data have program with an error message. been written to the l.c.d, module, output Line 20 assigns a value of ■ 4 goes high, taking the module into the &F12F8 to the variable SPORT mode where it treats received data as (serial port), and this is the character information. address of serial port 2. If you are m Everyday Practical Electronics, December 1998 899 Regular Clinic * » ■ail CIRCUIT sasf «i C SURGERY 4, W ALAN W/NSTANLEY We faAce o quick look at null modem leads for PhizzyB followers, and we check out relay ratings and light-dependent resistors too, with a simple light-dependent switch circuit. can also supply the null modem cable, see This stands to reason and looks obvious, Null Modems their advert elsewhere in this issue). but it can be very confusing especially and D-connectors Some bucket-part PCs have serial ports when confronted with D-connectors for the If you're interested in learning about mounted on the chassis with a separate first time. Luckily, manufacturers often how computers work, and how to use off-board bracket and ribbon cable, whilst annotate the pins of their connectors in your PC to program and control external many serial ports mount directly onto the the plastic moulding just to be sure, but circuitry, you need look no further than motherboard. The latter type seem to be whenever you are interpreting any inter- our new PhizzyB Computers series. This more common and use 9-pin D-connec- wiring diagrams, you can save yourself combines an interactive demonstration tool tors, but we have come across some ex- some wasted effort and delicate soldering with a real hardware PhizzyB connected to amples where 25-pin serial ports are used. by double checking whether the diagram your serial port. The numbering scheme for 9-pin and is the solder view or the pin view, and You can then assemble a program on 25-pin D-type female connectors, as used whether it's a female or male connector! your PC using the PhizzyB Simulator in the suggested null modem lead, seen To round off this topic. Fig. 2 shows the editor, and download it using the PBLink from the rear (solder) view of the sockets interwiring diagrams for 9-pin and 25-pin utility to a real PhizzyB. You can then run is shown in Fig.la. However, things can null modem leads. All views are of the the same program both on your PC as well get very confusing, especially when com- solder-sides of the connectors. Be sure to as the real thing; the real hardware version paring female and male D-connector num- confirm the type of serial port used on will then interface to other add-on units bering schemes, which are mirror images your own PC before you purchase any including (next month) a Liquid Crystal of one another. parts, though. Display and (later) an Infra-Red Com- Note the sequence of numbering on the munications System and more. D-connectors in Fig.lb, where this time Pull-ups and Relays The PhizzyB requires a null modem they are compared with the pin view rather Mr. Harsh Mehta had a variety of serial cable to be used to connect to the than the solder view. In a female connec- queries as follows: "host" PC. Such cables are also used tor, pin 1 is top-right, but is top-left in a Can you provide me some guidance with when connecting one PC to another, to male plug as shown. Obviously if you turn the following queries? I would like to know enable games or file transfers between two the plug around to in- PCs. The TxD and RxD signals cross over sert it into the socket, within the cable, to connect the transmit then you will soon see data of one port to the receive data of the that the pin numbers 9-PIN TO 9-PIN other. (Magenta Electronics offer a full kit of both components all o O (or ready assembled) PhizzyB and they correspond. 9-PIN TO 9-PIN PIN 25 TO PIN 35 PIN 3 TO PIN 2 wpAooooo/,^ wpAoooooooooooooy^ \o o o o/ ^ \o OOOOOOOOOO O/ v-' o O (SOLDER9-PIN FEMALE SIDE VIEW) 25-PIN(SOLDER FEMALE SIDE VIEW) PIN 5 - SIGNAL GROUND PIN 7 - SIGNAL GROUND 9-PIN TO 25-PIN PIN 3 - TxD PIN 2 - TxD O O PIN 2 ■ RxD PIN 3 - RxD 9-PIN TO 25-PIN g PIN 5 TO PIN 7 ^ F/g. 1a. Pin numbering schemes of 9-pin and 25-pin female PIN 2 TO PIN 2 O 1/ D-type connectors, shown from "solder" view. PIN 3 TO PIN 3 S Fig. 1b. Comparison of the schemes for 1 2 3 4 5 9-pin D-type male uOvooooo7n Ovooooo7n and female con- \o o o o/ ^ ^ \o o o o/ ^ nectors, taken from Fig. 2. Interwiring for 9-pin and 25-pin null the receptacle or modem leads. Female connectors are used 9-PIN FEMALE 9-PIN MALE D-CONNECTOR D-CONNECTOR pin view. The same throughout, although you should check the O (RECEPTACLE VIEW) (PIN VIEW) principle applies to connector used on your PC first. targe connectors. 900 Everyday Practical Electronics, December 1998 what is the use of Pull-Up and Pull-Down can handle providing they don't have to yourself, you can buy both a.c. and d.c. resistors and how do they function? interrupt the circuit as well. voltage coils. Flicking through a relay Also, with mechanical relays ! found the Bear in mind that a certain amount of manufacturer's catalogue, one popular following specifications. 24V D.C.I220V relay contact arcing and switch bounce range of plug-in relays includes both a A.C. What does this mean? Are there A.C. will occur when the load is switched, 110V d.c. coil (resistance 9,300 ohms, and D C. relays? How do they work? Last which eventually causes the contacts to current 12mA - as calculated by Ohm's of all, what is a Photo Cell and how does pit and "soot up": the makers will ob- Law), and a 110V a.c. coil (1.800 ohms it work? (By E-mail.) viously restrict the maximum values which 20mA). There's quite a lot to deal with, so let's the contacts can be expected to switch The current drawn by that a.c. coil start with your question concerning pull-up reliably. Somewhat higher currents can depends on its a.c. resistance or inductive resistors. These are used in logic circuits to often be carried by the contacts if they are reactance (which is why Ohm's Law ensure that a logic input is normally biased not expected to switch at those levels. doesn't work!), so a.c. and d.c. coils towards a logic "1", say +5V; then when Another specification is the maximum should not be considered as interchange- a logic 0 signal comes along, the input is switching capacity, which is the maxi- able merely because their voltage rating is taken low by the signal. mum permissible contact load in Watts or the same. Some a.c. coils may be specified Conversely, a pull-down resistor biases VA. This is not necessarily the same as the at 5()Hz or 60Hz operation or "dual that point to logic 0 (the OV rail) instead. value obtained by multiplying the maxi- frequency", remembering that frequency This is necessary if you want to ensure mum contact ratings (in Volts and Amps) has a bearing on the reactance of a coil and that a particular point is firmly held at a together, as it depends on the load being the current drawn. logic high or low, in between data being switched. The d.c. coil's resistance is of interest to received by that input. hobbyists because using Ohm's In discrete logic circuits, ordi- Law, we can calculate the direct nary resistors can be used whose current needed by the coil, and values are not particularly criti- then the additional circuitry can cal (say I Ok (kilohms) or so for be designed (e.g. using a transis- bipolar, or 1M (megohms) for tor buffer - see Circuit Surgery CMOS). A good example will last month). Don't forget to use a be seen in the PhizzyB con- reverse diode across a d.c. coil, structional article this month, in to shunt out the enormous hack- which a series of switches are TO PHIZZYB e.m.f. that a relay coil generates hooked to a PhizzyB input port INPUT PORT when it switches off. (see Fig. 3). This is created when the mag- The inputs to the switches (SI netic field which surrounds the to S8) are all wired to -(-5V coil suddenly implodes back into (logic high) and the outputs the windings and induces a volt- connect directly to the input data age in the coil. A 12V coil bus of the PhizzyB via a 20-way can produce as much as 300V ribbon cable. If any of the m . reverse e.m.f. which is clearly a switches are open (off) then the PULL-DOWN RESISTORS potential source of trouble for corresponding input data line (8 x 4k7) any components in the same could be left "floating" (un- circuit. connected) in an indeterminate If much larger loads are to be logic state, which may affect the S.1.LCOMMON' RESISTOR CONNECTION controlled (such as giant pumps reliability of the data read by the or process machinery), industrial PhizzyB from that port. Hence it engineers will employ what is was decided to force all unused effectively a huge version of a inputs low by using 4k7 pull- Fig. 3. PhizzyB input port experiment, using 8-way dip. power relay - a clunky device down resistors. switch and a s.i.l resistor network for putt-down resistors. called a contactor, which has Rather than use separate discrete resis- A simple resistive load (such as a separate coil and contacts mounted to- tors we utilised a single-in-line (s.i.l.) large heating element) is "kindest" to gether in a control box, along with package, which contains nine resistors all relay contacts but if complex electrical stop/start push-button controls. Check any commoned together (one is unused). This loads are used (including inductors, motors of the larger catalogues for details. common is connected to OV (logic low), to or fluorescent lighting, which include a produce a convenient bank of pull-down power factor correction capacitor) the Light-dependent switch resistors. (By wiring this terminal high to relay contacts must be de-rated substan- Looking at your final question, a "photo + 5V, a series of pull-up resistors could be tially as per the load's VA rating. I'm not cell" is just the popular name coined for created instead.) too sure why a minimum switching a photo-conductive cell, which is nothing Obviously, the common pin must be capacity is sometimes quoted, I guess it more than a light-dependent resistor (l.d.r.) correctly identified and wired low, hence relates to the minimum load required to based on cadmium sulphide (CdS). They the need to identify it as pin I. In the case overcome contact resistance and electrical respond to light in (he visible and infra red of the specified Bourns resistors, pin 1 is noise. spectrums. marked with a dot on the body. Other parameters for the contacts are An l.d.r. should not be confused with usually less critical, and include the a "photo-voltaic cell" which actually Relay Contacts operate time and release time, in Your question on relays next. The two milliseconds. Whether one period is main aspects to check are the contact greater than the other depends on the CIRCUIT THERAPY ratings and the relay coil values. A relay mechanical design of the relay. Circuit Surgery is your column If manufacturer such as Omron will quote the A figure of 10ms to 15ms is typical for a you have any queries or comments, following values for the coil and the please write to: Alan Winstanley, Circuit large power relay, but a small telecom- Surgery. Wimborne Publishing Ltd., Allen contacts. munications type relay used in a modem House, Hast Borough, Wimborne, Dorset, The maximum switching voltage is the could switch in 3ms. (Figures for con- BH21 IFF, United Kingdom. E-mail maximum open circuit load voltage that can tact bounce times of say 0-3ms to 0-5ms [email protected]. Please indi- be switched by the relay contacts. You will can sometimes be quoted which can be cate if your query is not for often see both d.c. and a.c. values quoted. critical to the work of lelecoms or logic publication. A personal reply cannot always be guaranteed The maximum switching current is designers.) but we will try to publish not surprisingly the maximum current (a.c. representative answers or d.c.) which the contacts are able to Coil Ratings in this column. , <• ^ ■■— interrupt without damage. This may some- Looking next at the coil ratings, two times be lower than the carry current, values will be specified, the coil voltage which is the (higher) value the contacts and its resistance. As you spotted for Everyday Practical Electronics. December 1998 901 creates a small voltage relative to in- cidental light levels. In the golden days of +9 - 12V D C. Everyday Electronics, using an l.d.r. in O a project (e.g. my world-beating Auto Nighllighl of July 1978 vintage) always implied using the ORP12, as manufac- 680s.*R5 ■< TR3 tured at the lime by Mullard. There BC558 are several alternatives readily available TR2 BC548 1 today. I ;0A As a final wrap this month, Fig. 4 shows TR1 a suggested circuit based on a transistor BC548 © Schmitt trigger, which combines an l.d.r. □RP12 R7 - with a transistor-driven relay to produce a r© 680s i ^ light-dependent switch suitable for dusk- VR1 * D2 ' to-dawn switching. Just the thing for these 22k . tN4001. winter months! D1 Component values are not critical, and LE.D. " [on] you should not be afraid to substitute for other parts to hand. See you next month! • Apologies to regular readers for any delay in responding to your growing mountain of letters and E-mail. Every item Fig.4. A light-operated, "snap action"circuit using an t.d.r. (tight-dependent resistor is read and I will attempt to reply as soon HI) as a sensor to control a transistor-driven relay. Components are not critical as possible. - Alan and preset VR1 sets the switching level. to Mr A. Flind at 22 Holway Hill, Taunton, Somerset, TA1 2HB. No callers. SHOP If you wish to do your own programming, the software is sup- to TALK II plied as TASM source and object files on a 3-5in. PC-compatible with David Barrington disk from the Editorial Offices, see EPE PCS Service page 913. There is an admin charge of £2.75 each (UK). For overseas readers, Handheld Function Generator the charge is £3.35 (surface mail) and £4.35 (airmail). If you are With such a small-sized project, obviously the choice of components an Internet user, it can be downloaded Free from our FTP site: for the Handheld Function Generator is crucial if they are to fit in the ftp://ttp.epemag.wimborne.co.uk/pub/PICS/MindPICkler It was also specified neat case. Also, the type and placing of the switches and on last month's Free CD-ROM. controls on the printed circuit board is important - so take care. Regarding the semiconductors: op.amps type OP296 (code NP22Y) Starting with the small sloping front case, it can be used either way and OP279 (code NP18U), 5V voltage reg. (AV35Q) and quad Schmitt up, the only source we have found is from Maplin (S 01702 554000) NAND gate 74HC132 (AE72P) all came from Maplin. You must pur- code KC96E. This case has a cable "knock-out" disc for lead entry and chase transistors with the L suffix as other types have different pinouts. is just made for the probe. The recommended ppbe comes in two The case used for the model is a Vero Patina type (Maplin NC90X) sections, metal tip and insulating cover. This was purchased from Far- that has been introduced to succeed their 200 series. This is a fairly nell (S 0113 263 6311) code 497-204 (black) or 497-198 (red), these expensive case and readers may care to choose their own style. come in packs of five. The printed circuit board is available from the EPE PCS Service, code The sub-min. p.c.b. mounting slide switches used in the model also 214. Finally, please heed the warning notice about PICkler's use! came from Farnell: 3-way double-pole, code 733-672; 2-way single- pole, code 733-647. The switch mounting socket-pins come as 32-way Fading Christmas Lights strips,and are cut to size with an art knife or side-cutters. These should You must use high quality capacitors in the Fading Christmas Lights be generally available and usually sold as "modular connectors" in- project where they are required to operate in association with the mains tended for mother-daughter boards. Try Maplin, code DC17T. Do not supply. They must be Class-X types rated for direct connection across forget to remove the plastic shroud from the switch centre pin sockets. the mains, and no doubt advertisers will be able to supply the required Turning our attention to the capacitors. These were ordered from the item. above two companies, although most of our components advertisers The chokes L1 to L3 may prove a problem. The type used in the should be able to come up with suitable caps; but check out sizes before prototype are known as "open toroidal" suppression types and were purchase. The polyester capacitors came from Maplin's layer range and ordered from Farnell (® 0113 263 6311), 581-239. The plastic bodied the sub-min. electrolytic from Farnell's MS7 series, code 490-684. pushswitches also only seem to be stocked by the above, code 140-690. Only use the specified 7621 CMOS op.amp in this circuit. Although A pre-programmed microcontroller type PIC16C54N can be ob- some alternative op.amps are quoted as capable of working at a 3V tained from the author at £9.50 (including postage). Please send supply, they either work poorly or not at all below 3V. The data for the cheques/postal orders to: B. Trepak, 20 The Avenue, London W13 7621 claims a minimum supply of around IV. The TDA7052 low-voltage 8PH. Mail order only - no callers. Overseas orders must include power amp should not be too hard to find. The same comment applies to payment in pounds sterling with a banker's draft drawn on a bank with a the screened stereo chassis jack socket. UK address. Moving on to the modular potentiometer package, with several acces- If you do intend to do your own programming, the software list- sory options. You need to order a "vertical" and a "horizontal" type here, ing is available from the Editorial Offices on a 3-5in. PC-compatible as a 100 kilohm type is not available in the vertical version. Unusually! disk, see EPE PCS Service page 913. There is a nominal admin horizontal and vertical in this case refer to the control shaft and not the charge of £2,75 each (UK), the actual software is Free. For overseas mounting of the presets. These controls were ordered through Maplin, readers, the charge is £3.35 surface mail and £4.35 airmail. If you codes DT46A (Fl) and DT35Q (V). are an Internet user, it can be downloaed Free from our FTP site: There are a number of alternative control shafts listed and the larger ffp://ftp.epemag.wimborne.co.uk/pub/PICS/xmaslights dual-shaft was ordered (Maplin DT49D) as it has serrated control ends. The printed circuit board is available from the EPE PCS Service, code As it is longer than needed, you will have to cut off the excess flush with 215. You MUST use a tamperproof plastic box for this project. the underside of the p.c.b. The small printed circuit board, including the N-cell board, is available PhizzyB I/O Board from the EPE PCS Service, code 213. Talking to Alan W, we found that, although he purchased his com- ponents for the PhizzyB I/O Board from Farnell, most items are stan- ERE Mind PICkler dard and it's a matter of shopping around for "best price". Alternative, Although construction of the EPE Mind PICkler project is not covered cheaper connectors, all from Maplin, would be: 20-way IDC non-latch until next month, we have included the components list, and made avail- box header, FJ14Q: 20-way 0-05in, IDC con., FG84F: 20-way flat IDC able the p.c.b., this month so that constructors can buy in parts now. cable, XR74R. Flaving said that, not too many items stand out as special, hard to find, The 4-section printed circuit board is available from the EPE PCS components. Service, code 216 (see page 913). So, let us start with the ready-programmed PIC. A 7-program Damp Stat PIC16F84 microcontroller is being made available to readers (mail order Not much to report on the parts needed for the Damp Stat project as only) by the author for the sum of just £10 inclusive UK. Overseas nearly all seem to be "off-the-shelf" types. You will probably be offered readers must add an extra £1 for postage and packing (overseas orders 18-tum or 22-tum square cermet presets, either will do. See PICkler must be in pounds sterling). entry regarding semiconductors. The printed circuit board is obtainable Orders should be sent to the following and all payments made out from the EPE PCS Service, code 209 (see page 913), 902 Everyday Practical Electronics. December 1998 WANT MORE I High precision scopes, FOR YOUR MONEY? | without the high cost NEW EW PROJECT KITS SURVEILLANCE I COMBINATION LOCK Versatile electronic lock High performance surveillance kits. Room I VCo ] comprising main circuit 6 separate keypad for transmitters supplied with sensitive electretl P remote opening of lock. Relay supplied. 3029-ICr microphones 6 battery holders/clips. All\ j £8.95 transmitters can be received on an ordinary §1 Hew; | LIGHT ALARM Protect your valuables. Alarm VHFFM radio. - I sounds if circuit detects smallest amount of light. MTX - Miniature 1I ALARMPlace in cashSIREN box HOdb etc. 3008-KT of ear piercing£4.50 noise. PCB 3V Transmitter j fits in box with has 2 x 35mm piezo elements built Easy to build 6 guaranteed to I into their own resonant cavity. Use as an alarm transmithigher voltage 500 metres 6 better (over aerial). 1000m 3-9V possible operation, with fI ir „-~ ' I sirenLED COUNTERor just for funl 3 digit 6-9VDC. basic 3015-KT event £8.75counter cir- Only 45x18mm. 3007-KT £4.95 I cuit on main board. Count 6 Reset switches & I debounce circuit on 2nd. Cascade 2 or 3 kits for MRTX - Miniature 9V Room Transmitter Most digital scopes today are capable of achieving only 8 bit 1 more digits. Box provided. 3001-KT £12.95 -Our 1000m best sellingrange (Up'bug'. to Super2 miles sensitive, with 18V high supply power &| I resolution. Pico Technology's new PC-based oscilloscopes represent FUNCTION GENERATOR Quad Op-Amp oscillator better aerial!). 9V operation. 45x19mm. 3018-KT |1 6 wave shaper circuit generates audio range £5.95 a quantum improvement in digital scope technololgy. The ADC-212 J square waves (6Hz-6KH2), triangle 6 pseudo sine offers 12 bit resolution, while its big brother, the ADC-216, is capable I outputs. 9VDC. 3023-KT £4.25 HighHPTX performance, - High Power 2 stage Room transmitter Transmitter gives greater I I LOGIC PROBE tests CMOS 6 TTL circuits 6 " stability b high quality reception r of 16 bit resolution. The scopes offer all the advantages associated 1 detects fast pulses. Visual b audio indication of ■ 1000m range with 9V I logic state. Full instructions supplied. 3024-KT battery. 6-12V L with PC based test & measurement, such as large colour displays I ROULETTE LED 'Ball' spins round the wheel, operation. OrV off I and a familiar Windows interface. Also, being Pico Technology I slows down & drops into a slot. 10 LEO'S, CMOS switch. Size 70x15mm. 3032-KT £6.951 decade counter b Op-Amp. Educational b funl VTX - Voice Activated Transmitter products, the high performance is not matched by a high price tag. 3006-KT £9.75 Powerful 2 stage voice activated I PELTIER JUNCTION HEAT PUMP Boil £r freeze Only operates when sounds are detected. 1km I I water instantly) Use for regulated cooling of range. Low standby current - conserves battery I 74T>(Z-212 / 216 - dual channel high resolution 1 temperature sensitive components 6 much more. power. Adjustable sensitivity 6 turn-off delay. Only 1r Heatsink required. 3066-KT £18.50 63*38mm. 3028-KT £7.95 Features Applications J 9V XENON TUBE FLASHER Transformer circuit TRI - Telephone Recording Interface I stepsXenon up tube. 9V batteryAdjustable supply flash to flash rate the(0.25-2 25mm See's). long Connect between phone line & cassette recorder. I ▼ Low cost ▼ Audio testing and analysis 1 3022-KT £10.95 Automatic-ally switches on tape when phone is f Mains harmonics testing j LM383 AUDIO AMPLIFIER Popular module for 48x32mm.used. Records 3033-1(7 all conversations. E5.95 Powered fromn line.li ▼ 90 dB spectrum analyser ▼ | any general (Class B) audio application. Typ. out- TRVS - Tape Recorder Vox Switch 12 and 16 bit resolution V Power supply design \I put3047-KT 10W £9.25@ 16V 6 2W speaker; 1W @ 9V 6 8W. Very sensitive, voice activated switch - automat-1 ▼ LED FLASHER 5 ultra bright red LED's flash in calty turns on cassette recorder when sounds are ▼ Analog telephony J sequence or randomly. Ideal for model railways. detected. Adjustable sensrtivrty & turn-off delay. I ▼ Up to 1250 ksps ▼ Vibration and noise I 3052-KT £4.50 115x19mm inc. mic. 3013-KT. £8.95 MULTI SEQUENCE LED FLASHER same as 3052- Ml IX - Miniature Telephone Transmitter ▼ Large buffer memory measurements 1 KT3037-KT above £4.50 but you have 7 patterns to choose from. Attaches anywhere to phone line. Transmits only f | LED DICE Classic intro to electronics b circuit when phone is used! Uses phone I AT)e-2t2 £299 /fDe-Tte £499 I I analysis. 7 LEO's simulate dice roll, slow down b line as aerial b power source. | I land on a number at random. 555 IC circuit. 500m range.3016-KT. 45x15mm, £4.95 Pf Products supplied with software, cables and power supply. Prices exclude VAT J DUAL3003-KT LED £7.75 DICE PIC 16C54 circuit performs simi- Two Station Intercom/Hard Wired Bug | lar function to 3003-KT above but two dice. Good amplifierEach unit (LM386). has its Turnown into speaker, a hard microphonewired bug byb IL Call for a free demo disk or visit our web site }J onintro disk. to micro-controllers.3071-KT £15.25 Software code supplied using 4 stand ribbon cable supplied to send power I 16C84 PIC PROGRAMMER Reads, programs b from the receiving unit to the remote 'bug' unit. 9V. j1 J verifies. Uses any PC parallel port. All hardware, 3027X7 £11.75 Tel: 01954 -211716 Fax: 01954 -211880 I software b documentation needed to learn b test Telephone Amplifier Kit [email protected] , www.picotech.com ]I STAIRWAYthis uC provided. TO HEAVEN3081-KT £25.50Tests hand-eye co-or- Pick-up coil b sensitive amplifier let you hear con-1 j dination. Press switch when green segment of versations without even holding the phone! Can be [ | LED lights to climb the stairway - miss b start used for surveillance purposes. 3055-KT. £9.25 I againlKT £7.75 Good intro to several basic circuits. 3005- SPEED CONTROLLER for any common DC motor FACXOR 1I imumup to 100V/5A.torque atPulse all widthspeeds. modulation 5-15VDC. gives 3067-KT max- I £17.50 THE EXPERTS IN RARE b | 3V/1.5V TO 9V BATTERY CONVERTER Replace UNUSUAL INFORMATION! expensive 9V batteries with economic 1.5V bat- Full details of all X-FACTOR PUBLICATIONS can be 1 teries. IC based circuit steps up 1 or 2 'AA' bat- found in our catalogue. N.B. Minimum order charge I1 teriesAM RADIO to give KIT9V/18mA. Tuned 3035-KT Radio £4.75Frequency front- for reports and plans is £5.00 PLUS normal P6P 1 end, single chip AM radio IC & 2 stages of SUPER-EAR LISTENING DEVICE Complete plans to Aidio - Tech I audio amplification. All components inc. speaker distantbuild your voices own and parabolic sounds throughdish microphone. open windows Listen and to IJ TRAINprovided. SOUNDS PCB 32x102mm. 4 selectable 3063-KT sounds £8.95 ~ even walls! Made from readily available parts. R002 I whistle blowing, level crossing bell, £3.50 Radio Modules at Lower Prices chugging, 6 'clickety-clack'. All TELEPHONE BUG PLANS Build you own micro-beetle I components inc. speaker supplied. telephone bug. Suitable for any phone. Transmits over I SGI £4 50 250 metres - more with good receiver. Made from easy than any catalogue, Guaranteed ! I AUDIO TO UGHT MODULATOR Controls intensity to obtain, cheap components. R006 £2.50 | of one or more lights in response to an audio LOCKS - How they work and how to pick them. This input. Safe, modern oplo-coupler design. Mains factart of filled lock report picking will than teach many you booksmore aboutwe have locks seen and at the 4 Part Catalogue RRP** Our Price IJ THREEvoltage TIMERexperience CIRCUTTS required. in one3012-KT kitl 3£5.75 PCB-s 6 all times the price. Packed with information and illustra- I components to make timers for a few seconds or up tions. flOW £3.50 TXM-418-A 1 to 21 years! Onboard relay outputs. 3085-KT £19.25 RADIO & TV JOKER PLANS We show you how to build (9V) £ 14 50 £ 10 99 8 CHANNEL IR TX/RX Controls 8 relays using IR three different circuits for disrupting TV picture TXM-418-F I remote control unit. 3072-KT £54.95 and sound plusneighbours FM radio! b theMay authorities!! upset your TXM-410-A or F Transmitter | ControlTELEPHONE 4 relays ACTIVATED from anywhere SWITCH down to DISCRETION REQUIRED. fl0J7£3.50 (3V) in world by phone. (Not BT INFINITY TRANSMfTTER PLANS approved). 3086-KT £58.95 WEB SITE famousComplete Infinity plans Transmitter. for building Once the SILRX-418-A I 10WMODULE STEREO Uses AMPLIFIER TDA2009 class AB installed on the target phone, device £29 95 £22.48 j audio power amp IC designed for See address at Moddverl acts like a room bug. Just call the target inn Of " y stereo applications. 3088-KT £9.95 phone 6 activate the unit to hear all room SILRX-418-A or F Recctver SILRX-418-F I 17W BRIDGE AMPLIFIER 40W of brute' power _ THE ETHERsounds. BOXGreat CALL for home/office INTERCEPTOR security! PLANS R019£3.S0 Grabs I 12VDC into 4W speakers. Ideal car booster amp. telephone calls out of thin air! No need to wire-in a 3091-KT £7.95 phone bug. Simply place this device near the phone | STEREO VU METER shows peak music power lines to hear the conversations taking place! ROTS £3.00 BIM-418-F | movingusing 2 barrows display. of 10 0-30db. LED's 3089-KT(green, £10.95yellow, red) BIM-433-F £ 58 00 £ 49.92 IR REMOTE TOGGLE SWITCH Use any remote MINI CCTV CAMERA I controlKT £9 50 unit to switch onboard relay on/off. 3058- Latest high quality FEATURES PC DATA ACQUISITION UNIT Enables your PC IR-sensitive 'Compact & light camera Approved to MPT 1340 I to monitor & control external events 6 devices monochrome PCB module. 54Wx38L TXM-173.225 through ifs parallel port. 3093-KT £99 95 camera module for x30mmH. 33 grams pendentlyPIC 16C71 controlFOUR SERVO4 servo MOTORmotors (notDRIVER supplied). Inde- •Low power consumption (ImW) or £42 00 £ 20.48 3102-KT £16.75 Video Intercom 12V 6C. 150mA TXM-173.225- UNIPOLAR STEPPER MOTOR DRIVER for any 5, 6 CCTV. Surveillance 'Low light requirement SecurityTXM-173 Trenemrtter 225-4689 | or 8 lead motors. 3 run modes. 3109-KT £17.50 etc. Simply plug •HighO.ILux quality, (IR LED high on) (lOmW) 1 LASER POINTER KIT 5mW Hitachi 670nm red into scart or video. resolution CCIR image. laser diode. Attractive plastic case supplied. 3070- 512x562 pixels KT £49.95 Six on-board IR •Video outpjit 1Vp-p/75ft ULTRASONIC MOVEMENT DETECTOR Xtal LED's. Less than •Lens 3.6mm, F1.8 RXM-173-4666 £64 75 £ 24 65 I controlled oscillator, detector circuit & edge half the size of a •Field of view 74*H x 55V mounted transducers on a cigarette packet! •Maintenance free J 75x40mm PCB. 4-7m range^ •Built-in electronically T I Adjustable sensitivity. ASSEMBLED UNIT: controlled auto-iris RXM-173 225-4666-60 ** rP**' Cetelogoe Company RRP efleetve Jan 1998 ex VAT I Outputs to drive external 30A 7-AS £69.95 •Internal synchronisation VHF Security Recerver relay/circuits. 9VDC. 3049-KT £12.95 Prices Exclude VAT and Carriage. P & P add £1.50 for | plus AUDIO • EDUCATIONAL • LASER • SECURITY • TEST GEAR • BOOKS b more I orders < £ 100 00 otherwise £6.00 of next day delivery. I Our high quality project kits are supplied with all components, fibre glass PCB's & comprehensive I I instructions. FREE CATALOGUE with order or send 2 x 1st Qass stamps (refundable) for details of over F 100 kits & publications. Mail order only. Please ADD £2.00 P. & P. to all orders (Europe £3, Rest of Telephone Sales 01992 576107 i World £4) & make chequeVPO's payable to Quasar Electronics. Goods normally despatch within 5 i 1 working days but please allow 28 days for delivery. Prices include VAT at 17-5%. nST Fax 01992 561994 Quasar Electronics Unit 14 Sunnningdale BISHOP'S STORTFORD Herts CM23 2PA Tel /Fax 01279 832269 E-mail: [email protected]. Web site: http://ourworld.compuserve.com/homepages/QuasarElectronics http://www.radio-lech.co.uk e-mail: [email protected] Everyday Practical Electronics, December 1998 903 Constructional Project =^r^\= i = 5Wr Mfi ELECTRONIC W& THERMOSTAT Mm ANDY FUND Part Two conesponding to a temperature increase of Control the environment inside about 10oF. your workshop/garage, or The network of resistors and poten- tiometers, comprising VR2, R4, R5, R6 anywhere dampness is likely and R7 with VR3, set up reference voltages corresponding to 40oF and 80°F to invade! for the upper and lower limits of the inside thermostat control's range. Resistors R4 and R5 "swamp" variations in the total value of VR3 and also provide a voltage This project is an extension to last CIRCUIT o month's T-Stat Electronic Thermo- equivalent to 60 F. DESCRIPTION There is little point in allowing the heat- stat controller system. Damp is often o a problem for anyone using a garage or The full circuit diagram for the Damp ing in Standby mode to operate above 60 F. outhouse of any kind as a workshop, and Stat is shown in Fig.l. It uses two It is also undesirable to let the internal tem- for the electronic hobbyist it can be par- LM335Z temperature sensors, one for perature fall to freezing, if only to prevent ticularly serious. inside and one for the outside temperature. ice forming in the p.c.b. etching fluid! The author uses part of a garage, parti- In this circuit they are fitted with calibra- Therefore, a dual clamping circuit tioned off and lined with sheets of thick tion trimming resistors so that their outputs prevents the signal from the top of resistor can be adjusted to correspond correctly. R2 from rising above the equivalent of expanded polystyrene for thermal insula- o o tion. Although not an ideal solution this The outside sensor 1C1 is supplied with 60 F or dropping below 40 F. This is was cheap to construct and is satisfac- a current of about I mA by resistor RI. accomplished by the two op.amps in IC2 tory so long as the damp is effectively This current also flows though R2 so the which act as comparators and clamp the controlled. voltage at the top of this resistor is about voltage from R2 through diodes D1 and 5lmV higher than the output from 1CI, D2 as appropriate. DAMP STAT To achieve this a special thermostat was - •• designed and built. Whilst the workshop : St*'' is in use the thermostat's Run setting is & selected and it operates in the usual way, heating the room to an adjustable preset temperature for comfort. At other times a Standby setting causes the inside tempera- ture to "track" l0oF above the outside ' temperature. * This low temperature differential coupled with good thermal insulation m i means the system is not too costly to run but there is always a tendency for dampness to migrate towards the outside. The system has been in operation for about twelve years now and works very well so mm readers seeking a solution to their own problems of damp may like to try it. The original circuit recently developed a minor fault. Whilst this proved to be only a faulty preset resistor in the in- ... dicator circuit it was difficult to repair since this older mains-powered design can at best be described as lethal! It was this — occurrence that led to the design of a new version using the much safer separate mains Power Controller unit described in Damp Stat p.c.b. together with last month's Power Controller and Room Tempera- the Nov '98 issue. ture Thermostat. Everyday Practical Electronics, December 1998 RAIL-TO-RAIL of the 7621. The simple solution to this or shows the current setting of the thermo- The output part of the circuit is built problem was to replace the 7621 with an stat control VR3. around dual op.amp IC4. lC4a simply OP296GP device which has a much better Power for the Damp Slat will normally buffers the input voltage selected by offset specification. be taken from the low-voltage supply in the switch S2. This will correspond to either Power Controller unit (last month), which is the Outside temperature plus 10oF or the TEMPERATURE regulated to 12V by 1C6 with decoupling current Interior setting from control VR3. METERING capacitors Cll to C14. Readers may have The buffered voltage from IC4a is fed Accurate voltage signals corresponding noticed that this circuit has plenty of low- to comparator IC4b, which compares it to both input and output temperatures are pass filtering and bypass capacitors. with the input from the inside tempera- available in this circuit so it is worth The reason for this is that about a year ture sensor IC3 and turns the output to providing an indicator. ICS forms a meter or so after the author's original design was the Power Controller unit on or off ac- amplifier providing indication through a built new neighbours moved into an cordingly through transistor TR1. Resis- 100p.A moving-coil meter. adjoining property. They turned out to tors Rll and RI2 provide positive feed- Preset control VR5, together with resis- be CB enthusiasts, and each time the back equivalent to about one degree F for tors R15 and RI4, allow adjustment of the "rig" was keyed the workshop heating a positive switching action. L.E.D. D3 zero setting. Span adjustment is not re- sprang into life! Extensive h.f. suppression indicates when the output is On whilst RI3 quired since the combination of resistors and bypassing was required to cure the provides a low impedance path to negative R16 and R17 provide an accuracy within problem, so this new version has this for the control connection when it is Off. 1 % for a span of 0oF to 100oF. included from the outset. A special feature of 1C4 is that its Although an indication is unlikely to be outputs are "rail-to-rail". The circuit was needed below about 20oF, the indicated CONSTRUCTION originally designed with the 7621 device value is still easy to read and this scale Most of the components for this project which also has this feature, as used by does avoid the need for recalibrating the are mounted on a small printed circuit the simple Room Temperature Thermostat meter scale, which will almost certainly be board (p.c.b.), as shown in Fig.2. This featured last month. However, a difference marked 0 to 100. Resistor R18 limits the board is available from the EPE PCS of several degrees between indicated and meter current to a safe value if the input is Service, code 209. operating temperatures soon became ap- overdriven. Switch SI selects the signal Construction should be straightforward parent due to the high input offset voltages from the outside sensor or the inside one, if resistors, diodes and small capacitors are VR2 -W —^"1 MODE TR1 I STANDBY | BC184L D1 IC4d 1N4148 150ft VR3 WW-i C2b IC4a LM358 IRUNI 4 'u SET TEMP H12 1N4148 470n ED N IC2a TB1/1 n TB2 1 HI 3 WE ADJ Au : 47f o IC1 lOOn loon IC3 TB3/1 LM335Z LM335Z VH4 4, On 470n ,'K OUTPUT EXTERNAL 100n NTERNAL SENSOR SENSOR TB2/2 + 12V IC6 TB3/2 78L12 O I ■ P9 R14' 12k- Ml 1 METER lOOjtA (F.S.D.) SELECT C8 i 470n i —w— icse C12 I C13 I IC5a LM358 P10 V lOOn I lOOn < R15 LM358. 2k/ -^V\A— C10 lOOn lOOn C11 I C14 t 10M 1 100M 1 VRS H18 TB3/3 —O GND Fig. 1. Complete circuit diagram for the Damp Stat. The circuit is powered from one of last month's two Power Controllers. Everyday Practical Electronics, December 1998 905 fitted first, followed by larger or vertically mains Power Controller units (last month) should be inserted, the meter should be taller components such as 1C6, TRI, ter- or from a bench supply in which case it connected to points J( +) and K{ — ) and a minal blocks and electrolytic capacitors. should be set to give about 15V. The flying lead can be fitted to the meter circuit Finally, d.i.l. sockets should be used for presence of the 12V regulated supply from input point /. 1C2, 1C4 and ICS, the i.c.s should not be IC6 should be checked. A test input is needed for checking the inserted at this stage. The meter circuit should be calibrated sensor inputs, the easy way to provide one first as this can be used for checking and is to connect a 1 kilohm potentiometer TESTING setting up the rest of the circuit. ICS with two resistors across the outside sensor Testing begins with the provision of a supply voltage, either from one of the P7 P8 . 8 TRI IC6 R18 OUT OUT n :ok> TB3 COMPONENTS PII • D • @ +VE •PA m P10« IC2 IC4 n • 8 /.[ Resistors ICS R1, R6, R8 8k2 (3 off) fVt 0 • 1 • (IC1, TB" C14 R2 47n GND •O • TR? R11 R3 22k 2® C11 R4, R5 1 son (2 off) R7, R15 2k7 (2 off) ♦VE GND R9, RIO 100k (2 off) R11 toon o—o R12 220k R13 ik See PI R14 12k ©tfltPitfe) R16 5k6 Moll R17 820k TALK o- R18 39k Page 209 1 All 0-6W1% metal film Z5 I Potentiometers VR1, VR4 10k 22-turn square cermet preset (2 off) VR2, VR5 1 k 22-turn square cermet Fig.2. Printed circuit board component layout and full size underside copper foil preset (2 off) master pattern for the Damp Stat. VR3 Ik rotary carbon, lin. | Capacitors C1,C5, C6, C7, C8 470n resin-dipped ceramic JUU> (5 off) C2, C3, C4, C9, C10, - I C12, C13 100n resin-dipped ceramic 1 (7 off) C11 10p, radial elect. 63V C14 100p radial elect. 35V | Semiconductors D1, D2 1N4148 signal diode (2 off) 03 5mm red l.e.d., 10mA type TR1 BC184L npn silicon transistor Layout of components on completed printed circuit board. IC1, IC3 LM335Z temperature sensor (2 off) IC2, ICS LM358 dual op.amp (2 off) METER SET IC4 OP296GP dual CMOS SELECT TEMP |MODE | op.amp, rail-to-rail output . f- ■: IC6 78L12 12V 100mA IN 0UT positive voltage /# ^ %\ regulator ML1 nj Miscellaneous SI 3-way single-pole rotary D3 switch S2 s.p.d.t. toggle switch // ME1 IOOjjlA moving-coil meter TB1, TB2 2-way p.c.b. mounting terminal block, low V02 1 0 profile (2 off) TB3 TB3 3-way p.c.b. mounting P11 2 0 block, low profile P10 Printed circuit board available from IC4 3 0 the EPE PCS Service, code 209; plastic 0 ■ or metal case, size and type to choice; TB1 8-pin d.i.l. socket (3 off); plastic knob; 0 multistrand connecting wire; solder pins; 'yo© m | solder etc. 1 -VE TO OUTSIDE vE -VE TO POWER -► +VE SENSOR TO INSIDE CONTROLLER Approx Cost (IC1) SENSOR 0UT Guidance Only (IC3) excluding meter Fig. 4. Interwiring details from p.c.b. to off-board components. 906 Everyday Practical Electronics, December 1998 Completed circuit board showing the -O TOTBt/t (+) external, internal and power supply st n terminal blocks. * A ■O TO TB1/2 (-) DVM. If the quiescent temperature is not Fig. 3. Test input circuit diagram. loo far away from this value, it should be sufficient to just set the presets to obtain the correct output for the current input TBI/I and TBI/2 as shown in Fig,3. used to monitor the applied test input. As temperature, using the circuits" own meter This will provide input voltages equivalent this is raised and lowered past the set point as an indicator for this adjustment. to about -350F to I200F. Using a DVM D3 should turn on and off. indicating cor- In the author's installation the interior (digital voltmeter), the voltage across this rect operation. sensor is fitted into a plastic 35mm film can be adjusted to 2-832V which is equiv- Following this, it only remains to fit container mounted some distance from the alent to 50oF or half-scale on the meter. the circuit into a suitable case and make control box. This was partly because the The meter input from point / should the necessary external connections to the older circuit generated some heat and with now be connected to TB1/1 and the multi- p.c.b. as shown in Fig.4 to complete the this new version it could be fitted into the turn preset VR5 adjusted for a half-scale main part of the project. same case as the p.c.b. The choice is up reading. Control VR3 should now be tem- to the constructor, but whichever is used, porarily connected, and the meter can be 1 2 3 4 5 6 7 holes should be provided in the case to used to monitor its bottom connection to allow air to flow around it. point D whilst this is adjusted with preset The external sensor will not need to Ir.0 VR2 for a reading of 40°F. •ipt vR- have such a rapid response but it will Next, 1C2 should be inserted and the probably have to be weatherproof. The Standby voltage from point C should be □ •©•oooooo prototype was fitted into a small plastic monitored with the meter whilst the test • • • o • o o • box and potted with some silicone rubber input is raised and lowered. It should be B 0«000000*0 compound. This obviously makes it im- found that this input will not go above • ooo»o»oo» possible to repair, but in twelve years it 60°F or below 40oF, indicating correct 23456789 10 has yet to fail. It should, of course, be operation of the clamp circuit. positioned where it is sheltered from sun- We can now fit IC4 and the input to Fig. 5. Stripboard details for Sensors. light, rain, strong winds and other sources resistor R9, point F, connected to the of heat or cold which might interfere with wiper of VR3. L.E.D. D3 should be SENSORS its correct operation. temporarily connected and a 1 kilohm The two sensors should now be built The economy of operation of this cir- resistor should be connected between the and calibrated. Both are assembled on cuit obviously depends upon good insula- output and OV connections of TB3 so that small pieces of 0-1 in. matrix stripboard as tion and draughtproofing of the premises D3 will light when the output is On. shown in Fig.5, to which it is fitted. Provided this is The test input should now be moved to The official way to calibrate an reasonably efficient it should help to the terminal block for the interior sensor LM335Z sensor i.e. is to raise it to a minimise damp with surprising efficiency, IC3, TB2. The meter can be used to set the temperature of 250C, then adjust the preset giving long-term protection to vital equip- thermostat control VR3 to, say 60oF, then to obtain an output of 2-982V using a ment and paperwork. LM335Z Precision Temperature Sensor The LM335Z is a temperature sensing i.e. It acts a bit like a Divide by 100 Zener diode, in that when fed with a fairly constant current of Add 2-7315 between 40(VA and 5mA, usually with a single resistor from = Output Voltage . . . the positive supply, a voltage develops across it. This volt- age is linearly proportional to temperature at the rate of Voltage to Temperature: lOmV per degree C. Volts.. . The starting point for this voltage, however, is "absolute Subtract 2-7315 zero", which most readers will recall from their schooldays Multiply by 100 as being the equivalent of -273-15 degrees C. This means = Degrees C .. . that at 0 degrees C as we know it. "freezing point", the Multiply by 9 output from the LM335Z will be about 2-7315 volts. Divide by 5 The accuracy of the device isn't spot-on as supplied, it is Add 32 quoted as being within two degrees over its operating range = Degrees F ... of -10oC to -TlOCFC. However, this can be improved to 0 within 1 C with a simple preset adjustment which is shown in In Comparison the Damp Stat project. The LM35CZ and LM35DZ are similar devices with built-in current sources, already trimmed to within one degree C. Calculations They have internal offset compensation so that output starts Calculation procedures to convert temperature to voltage at 0 degrees C. and vice-versa are as follows: However, use of a separate output terminal means that Temperature to Voltage: three connections are required to a remote sensor instead Degrees F.. . of just two, and they are also more expensive. Where Subtract 32 measurements are to be made below 0 degrees C a circuit Multiply by 5 capable of working below the negative supply to the i.e. is Divide by 9 required. These limitations make the cheaper LM335Z the Degrees C... preferred choice for this project. Everyday Practical Electronics, December 1998 907 VIDEOS ON ELECTRONICS n UCANDO A range of videos (selected by EPE editorial staff) designed to provide acA^DO instruction on electronics theory. Each video gives a sound introduction and o grounding in a specialised area of the subject. The tapes make learning both easier and more enjoyable than pure textbook or magazine study Each video •n i uses a mixture of animated current flow in circuits plus text, plus cartoon instruction etc., and a very full commentary to get the points across. The tapes originate from VCR Educational Products Co, an American supplier. (All videos are to the UK PAL standard on VHS tapes,) DIGIT At TWO BASICS VT201 to VT206 is a basic electronics VCR MAINTENANCE VT102 84 minutes: Introduction to VCR course and is designed to be used as a Repair. Warning, not for the beginner. complete series, if required. Through the use of block diagrams this VT201 54 minutes. Part One; D.C. Circuits, This video will take you through the various video is an absolute must for the beginner. circuits found in the NTSC VHS system. Series circuits, parallel circuits. Ohms law, You will follow the signal from the input how to use the digital multimeter and much to the audio/video heads then from the RADIO more. Order Code VT201 heads back to the output. VT401 61 minutes. A.M. Radio Theory. The most VT202 62 minutes. Part Two; AC. Circuits. This Order Code VT102 complete video ever produced on a.m. radio. VT103 35 minutes: A step-by-step easy to Begins with the basics of a.m. transmission and is your next step in understanding the basics of follow procedure for professionally clean- electronics. You will learn about how coils, ing the tape path and replacing many of proceeds to the five major stages of a.m. recep- transformers, capacitors, etc are used in com- the belts in most VHS VCR's. The viewer tion. Learn how the signal is detected, converted mon circuits. Order Code VT202 will also become familiar with the various and reproduced. Also covers the Motorola C- Vr203 57 minutes. Part Three; Semiconductors. parts found in the tape path. QUAM a.m. stereo system. Order Code VT401 Gives you an exciting look into the world Order Code VT103 VT402 58 minutes. FM. Radio Part 1. F.M. basics of semiconductors. With basic semiconduc- including the functional blocks of a receiver. tor theory. Plus 15 different semiconductor Plus r.f. amplifier, mixer oscillator, i.f. amplifier, devices explained. Order Code VT203 DIGITAL limiter and f.m. decoder stages of a typical f.m. receiver. Order Code VT402 Now for the digital series of six videos. VT403 58 minutes. F.M. Radio Part 2. A con- This series is designed to provide a tinuation of f.m. technology from Part 1. good grounding in digital and computer Begins with the detector stage output, proceeds I technology. to the 19kHz amplifier, frequency doubler, Sv 15 QOOj VT301 54 minutes. Digital One; Gates begins stereo demultiplexer and audio amplifier stages. with the basics as you learn about seven Also covers RDS digital data encoding and of the most common gates which are used decoding. Order Code VT403 GV in almost every digital circuit, plus Binary t: notation. Order Code VT30i MISCELLANEOUS VT302 55 minutes. Digital Two; Flip Hops will VT501 58 minutes. Fibre Optics. From the fun- further enhance your knowledge of digi- damentals of fibre optic technology through tal basics. You will learn about Octal cable manufacture to connectors, transmitters and Hexadecimal notation groups, flip-flops, and receivers. Order Code VT501 counters, etc. Order Code VT302 vr502 57 minutes. Laser Technology A basic in- VT303 54 minutes. Digital Three; Registers and troduction covering some of the common uses of VT204 56 minutes. Part Four; Power Supplies. Displays is your next step in obtaining a solid laser devices, plus the operation of the Ruby Guides you step-by-step through different sec- understanding of the basic circuits found in Rod laser, HeNe laser. COo gas laser and semi- tions of a power supply. Order Code VT204 today's digital designs. Gets into multiplexers, conductor laser devices. Also covers the basics VT205 57 minutes. Part Five; Amplifiers. Shows registers, display devices, etc. of CD and bar code scanning. you how amplifiers work as you have never Order Code VT303 Order Code VT502 seen them before. Class A, class B, class C, VT304 59 minutes. Digital Four; DAC and ADC op.amps. etc. Order Code VT205 shows you how the computer is able to com- VT206 54 minutes. Part Six; Oscillators. Oscil- municate with the real world. You will learn lators are found in both linear and digital cir- about digital-to-analogue and analogue-to-digi- cuits. Gives a good basic background in oscil- tal converter circuits. Order Code VT304 lator circuits. Order Code VT206 VT305 56 minutes. Digital Five; Memory Devices introduces you to the technology used in many of today's memory devices. You will learn all TP about ROM devices and then proceed into each PROM, EPROM, EEPROM, SRAM, DRAM, and £34*95 MBM devices. Order Code VT305 inc. VAT & postage VT306 56 minutes. Digital Six; The CPU gives ^Order 8 or more get one extra FREE^ you a thorough understanding in the basics of the central processing unit and the input/output Order 16 get two extra FREE circuits used to make the system work. Order Code VT306 ORDERING: Price includes VIDEO ORDER FORM postage to anywhere in the world. Full name;. OVERSEAS ORDERS: We use the Address: ... VAT portion of the price to pay for airmail postage and packing, wherever you live in the world. Just send £34.95 per tape. All payments Post code: Telephone No.. in £ sterling only (send cheque or money order drawn on a UK bank). Signature: Send your order to: Direct Book Service, 33 Gravel Hill, I I I enclose chequc/PO payable to WIMBORNE PUBLISHING LTD Merlcy, Wimbomc, Dorset BH21 ] Please charge my Visa Mastercard: Card expiry date 1RW (Mail Order Only) Card No: Direct Book Service is a division of Wimbome Publishing Ltd. Please send video order codes:. Tel: 01202 881749 tax: 01202 841692 Videos are normally sent within seven days of receipt of order. Please continue on a separate sheet of paper if necessary. E22 DIRECT BOOK SERVICE The books listed have been selected by Everyday Practical Electronics editorial staff as being of special interest to everyone involved in electronics v and computing. They are supplied by mail order to V your door. Full ordering details are given on the -- last book page. FOR ANOTHER SELECTION OF BOOKS SEE THE NEXT TWO MONTH'S ISSUES. is! Note our UK postage costs just £1.50 no matter how many books you order! 3a ELECTRONICS TEACH-IN 88/89 INTRODUCING MICROPROCESSORS Mike Tooley B.A. (published by Everyday Practical Electronics) A complete course that can lead successful readers to the award of a City and Guilds Certificate in Introductory ELECTRONICS PROJECTS DISCOVERING ELECTRONIC CLOCKS Microprocessors (726/303). The book contains evetything USING ELECTRONICS WORKBENCH FREE W. D. Phillips you need to know including full details on registering for plus FREE CD-ROM CD-ROM This is a whole book about designing and making assessment, etc. M. R Horsey electronic clocks. You start by connecting HIGH and Sections cover Microcomputer Systems, This book offers a wide range of tested circuit mod- LOW logic signals to logic gates. You find out about Microprocessors, Memories, Input/Output, Interfacing ules which can be used as electronics projects, part of and then build and test bistables, crystal-controlled and Programming. There are various practical an electronics course, or as a hands-on way of get- astables, counters, decoders and displays. All of these assignments and eight Data Pages covering popular ting better acquainted with Electronics Workbench. With subsystems are carefully explained, with practical work microprocessors. circuits ranging from 'bulbs and batteries' to complex supported by easy to follow prototype board layouts. And excellent introduction to the subject even for those systems using integrated circuits, the projects will appeal Full constructional details, including circuit diagrams and who do not wish to take the City and Guilds assessment. to novices, students and practitioners alike. a printed circuit board pattern, are given for a digital 80 pages l>J J. F JIJ.!.' i £2.45 Electronics Workbench is a highly versatile computer electronic clock. The circuit for the First Clock is modified simulation package which enables the user to design, test and developed to produce additional designs which include ELECTRONICS TEACH-IN No. 7. FREE and modify their circuits before building them, and to plan a Big Digit Clock, Binary Clock, Linear Clock, Andrew's Clock ANALOGUE AND DIGITAL RGB layouts on-screen. All the circuits in the book are (with a semi-analogue display), and a Circles Clock. All of ELECTRONICS COURSE SOFTWARE provided as runnable Electronic Workbench files on the these designs are unusual and distinctive. (published by Everyday Practical Electronics] enclosed CD-ROM, and a selection of 15 representative This is an ideal resource for project work in GCSE Alan Winstanley and Keith Dye B.Eng(Tech)AMIEE circuits can be explored using the free demo version of Design and Technology: Electronics Product, and for This highly acclaimed EPE Teach-In series, which included the application. project work in AS-Level and A-Level Electronics and the construction and use of the Mini Lab and Micro Lab Contents: Some basic concepts; Projects with switches, Technology. test and development units, has been put together in LEDs, relays and diodes; Transistors; Power supplies; 194 pages, A4 spiral bound £16.50 book form. Additionally, EPT Educational Software have Op.amp projects; Further op.amp circuits; Logic gates; Real developed a GCSE Electronics software program to com- logic circuits; Logic gate multivibrators; The 555 timer; DOMESTIC SECURITY SYSTEMS pliment the course and a FREE DISK covering the first two Flip-flops, counters and shift registers; Adders, comparators A. L. Brown parts of the course is included with the book. and multiplexers; Field effect transistors; Thyristors, triacs This book shows you how, with common sense and basic An interesting and thorough tutorial series aimed speci- and diacs; Constructing your circuit; Index. do-it-yourself skills, you can protect your home. It also fically at the novice or complete beginner in electronics. 227pages l» J7. Mil.?.?! fl 11 >vl £14.99 gives tips and ideas which will help you to maintain and The series is designed to support those undertaking either A BEGINNER'S GUIDE TO MODERN ELECTRONIC improve your home security, even if you already have GCSE Electronics or GCE Advanced Levels, and starts COMPONENTS an alarm. Every circuit in this book is clearly described with fundamental principles. R. A. Penfold and illustrated, and contains components that are easy to If you are taking electronics or technology at school The purpose of this book is to provide practical informa- source. Advice and guidance are based on the real ex- or college, this book is for you. If you just want to tion to help the reader sort out the bewildering array of perience of the author who is an alarm installer, and the learn the basics of electronics or technology you must components currently on offer. An advanced knowledge designs themselves have been rigorously put to use on make sure you see it. Teach-In No. 7 will be invaluable of the theory of electronics is not needed, and this some of the most crime-ridden streets in the world. if you are considering a career in electronics or even book is not intended to be a course in electronic theory. The designs include all elements, including sensors, if you are already training in one. The Mini Lab and The main aim is to explain the differences between detectors, alarms, controls, lights, video and door entry software enable the construction and testing of both components of the same basic type (e.g. carbon, carbon systems. Chapters cover installation, testing, main- demonstration and development circuits. These learn- film, metal film, and wire-wound resistors) so that the tenance and upgrading. ing aids bring electronics to life in an enjoyable and right component for a given application can be selected. 192 pages £12.99 interesting way: you will both see and hear the electron A wide range of components are included, with the MICROCONTROLLER COOKBOOK in action! The Micro Lab microprocessor add-on system emphasis firmly on those components that are used a Mike James will appeal to higher level students and those develop- great deal in projects for the home constructor. The practical solutions to real problems shown in this ing microprocessor projects. 170 pages Kffl M f T.T! fl: I : Li £4.99 cookbook provide the basis to make PIC and 8051 160 pages RTfPWCTfTSiFl £3.95 devices really work. Capabilities of the variants are examined, and ways to enhance these are shown. A survey of common interface devices, and a descrip- tion of programming models, lead on to a section on development techniques. The cookbook offers an intro- duction that will allow any user, novice or experienced, WINDOWS 95 EXPLAINED built-in ports provide what is often a much easier and to make the most of microcontrollers. R R. M. Oliver and N. Kantaris hassle-free way of interfacing your own circuits to a 240 pages |»U. M MX>T> n 11 £19.99 If you would like to get up and running, as soon as pos- PC. In particlar, a PC printer port plus a small amount sible, with the new Windows 95 operating system, then of external hardware provides a surprisingly versatile A BEGINNER'S GUIDE TO TTL DIGITAL ICs this is the book for you. input/output port. The PC "games" port is less useful for R. A. Penfold The book was written with the non-expert, busy person general interfacing purposes, but it can be useful in This book first covers the basics of simple logic circuits in mind. It explains the hardware that you need in order to some applications. in general, and then progresses to specific TTL logic run Windows 95 successfully, and how to install and op- This book provides a number of useful PC add-on integrated circuits. The devices covered include gates, timize your system's resources. It presents an overview of circuits including the following; Digital input/output ports; oscillators, timers, flip/flops, dividers, and decoder cir- the Windows 95 environment. Analogue to digital converter; Digital-to-Analogue Con- cuits. Some practical circuits are used to illustrate the Later chapters cover how to work with programs, verter; Voltage and current measurement circuits; Resis- use of TTL devices in the "real world" folders and documents; how to control Windows 95 and tance meter; Capacitance meter; Temperature measure- 142 pages HJ/.flf £4.95 use the many accessories that come with it; how to use ment interface; Biofeedback monitor; Constant voltage DOS programs and, if necessary, DOS commands and model train controller; Pulsed model train controllers; how to communicate with the rest of the electronic world. Position sensor (optical, Hall effect, etc.); Stepper motor ELECTRONIC MODULES AND SYSTEMS FOR 170 pages £5.95 interface; Relay and LED drivers; Triac mains switching BEGINNERS interface. Owen Bishop 179 pages £4.99 This book describes over 60 modular electronic circuits, INTERFACING PCs AND COMPATIBLES how they work, how to build them, and how to use R. A. Penfold them. The modules may be wired together to make Once you know how, PC interfacing is less involved than HOW TO EXPAND, MODERNISE AND REPAIR PCs hundreds of different electronic systems, both analogue interfacing many eight-bit machines, which have tended AND COMPATIBLES (Revised Edition) and digital. To show the reader how to begin build- to use some unusual interfacing methods. R. A. Penfold ing systems from modules, a selection of over 25 This book gives you: A detailed description of the lines Not only are PC and compatible computers very ex- electronic systems are described in detail, covering present on the PC expansion bus. A detailed discussion of pandable, but before long most users actually wish to such widely differing applications as timing, home the physical characteristics of PC expansion cards. The take advantage of that expandability and start upgrad- security, measurement, audio (including a simple radio I/O map and details of the areas where your add-on can ing their PC system. Some aspects of PC upgrading receiver), games and remote control. be fitted. A discussion of address decoding techniques. can be a bit confusing, but this book provides advice 200 pages r-TTTfi M :1 £3.95 Practical address decoder circuits. Simple TTL 8-bit input and guidance on the popular forms of internal PC ex- PRACTICAL ELECTRONICS CALCULATIONS AND and output ports. Details of using the 8255 parallel inter- pansion, and should help to make things reasonably FORMULAE face adaptor. Digital to analogue converter circuits. In fact straightforward and painless. Little knowledge of com- F. A. Wilson, C.G.I.A., C.Eng., F.I.E.E.. F.I.E.R.E., F.B.I.M. everything you need to know in order to produce success- puting is assumed. The only assumption is that you can Bridges the gap between complicated technical theory, ful PC add-ons. operate a standard PC of some kind (PC, PC XT, PC AT, and "cut-and-tried" methods which may bring success 80 pages r> JT HT?.? fl :T £3.95 or an 80386 based PC). in design but leave the experimenter unfulfilled. A The subjects covered include: PC overview; Memory strong practical bias - tedious and higher mathematics upgrades; Adding a hard disk drive; Adding a floppy have been avoided where possible and many tables EASY PC INTERFACING disk drive; Display adaptors and monitors; Fitting have been included. R. A. Penfold a maths co-processor; Keyboards; Ports; Mice and The book is divided into six basic sections: Units and Although the internal expansion slots of a PC provide digitisers; Maintenance (including preventative main- Constants, Direct-Current Circuits, Passive Components, full access to the computer's buses, and are suitable for tenance) and Repairs, and the increasingly popular Alternating-Current Circuits, Networks and Theorems, user add-ons, making your own expansion cards re- subject of d.i.y. PCs. Measurements. quires a fair amount of expertise and equipment. The 156 pages J /■ M fl:] £5.99 256 pages Temporarily out of print Everyday Practical Electronics. December 1998 909 Theory and Reference FREE Bebop To The Boolean Boogie Bebop Bytes Back CD-ROM By Clive (call me Max) By Clive "Max" Maxfield Maxfield and Alvin Brown ORDER CODE BEB1 Bebop BYTES Back ORDER CODE BEB2 An Unconventional fiuide to £24.95 £29.95 Computers 470 pages. Large format Over 500 pages. Large Specially imported by EPE- format Excellent value An Unconventional Guide to Specially imported by Electronics Fundamentals, EPE - Excellent value Components and Processes An Unconventional Guide This book gives the "big picture" of To Computers digital electronics. This indepth, highly readable, up-to-the-minute guide shows Plus FREE CD-ROM which includes:. % you how electronic devices work and how Fully Functional Internet-Ready Filly functional IntBWt-t they're made. You'll discover how transistors operate, how printed circuit Virtual Computer with Interactive Virluol Computtr with boards are fabricated, and what the innards of memory ICs look like. You'll Labs jltcroctirt Laos also gain a working knowledge of Boolean algebra and Karnaugh maps, This follow-on to Bebop to the and understand what Reed-Muller logic is and how it's used. And there's Boolean Boogie is a multimedia ex- much, MUCH more (including a recipe for a truly great seafood gumbo!). travaganza of information about how Hundreds of carefully drawn illustrations clearly show the important computers work. It picks up where "Bebop I" left off, guiding you through points of each topic. The author's tongue-in-cheek British humor makes it the fascinating world of computer design . . . and you'll have a few a delight to read, but this is a REAL technical book, extremely detailed and chuckles, if not belly laughs, along the way. In addition to over 200 accurate. A great reference for your own shelf, and also an ideal gift for a megabytes of mega-cool multimedia, the accompanying CD-ROM (for friend or family member who wants to understand what it is you do all Windows 95 machines only) contains a virtual microcomputer, simulating day.... the motherboard and standard computer peripherals in an extremely realistic manner. In addition to a wealth of technical information, myriad DIGITAL ELECTRONICS - A PRACTICAL APPROACH FREE nuggets of trivia, and hundreds of carefully drawn illustrations, the book With FREE Software: Number One Systems - EASY-PC SOFTWARE Professional XM and Pulsar (Limited Functionality) contains a set of lab experiments for the virtual microcomputer that let Richard Monk you recreate the experiences of early computer pioneers. If you're the Covers binary arithmetic, Boolean algebra and logic gates, combina- slightest bit interested in the inner workings of computers, then don't dare tion logic, sequential logic including the design and construction of to miss this one! asynchronous and synchronous circuits and register circuits. Together with a considerable practical content plus the additional attraction of its close association with computer aided design including the FREE DIGITAL GATES AND FLIP-FLOPS software. Ian R. Sinclair There is a 'blow-by-blow' guide to the use of EASY-PC Professional XM This book, intended for enthusiasts, students and technicians, seeks to (a schematic drawing and printed circuit board design computer package). establish a firm foundation in digital electronics by treating the topics of The guide also conducts the reader through logic circuit simulation using gates and flip-flops thoroughly and from the beginning. Pulsar software. Chapters on p.c.b. physics and p.c.b. production tech- niques make the book unique, and with its host of project ideas make it an Topics such as Boolean algebra and Karnaugh mapping are explained, ideal companion for the integrative assignment and common skills com- demonstrated and used extensively, and more attention is paid to the ponents required by BTEC and the key skills demanded by GNVQ. The subject of synchronous counters than to the simple but less important principal aim of the book is to provide a straightforward approach to the ripple counters. understanding of digital electronics. No background other than a basic knowledge of electronics is assumed, Those who prefer the 'Teach-In' approach or would rather experiment and the more theoretical topics are explained from the beginning, as also with some simple circuits should find the book's final chapters on printed are many working practices. The book concludes with an explanation of circuit board production and project ideas especially useful. microprocessor techniques as applied to digital logic. 250 pages £16.99 200 pages fiJE HTW* M jMTiTil £8.95 Audio and Music AN INTRODUCTION TO LOUDSPEAKERS AND Also included is the circuit and layout of an inexpen- But fear not, setting up and using a computer-based ENCLOSURE DESIGN sive but highly successful twin-notch filter, and how to music making system is not as difficult as you might V. Capel operate it. think. This book explores the various features, good points 92 pages Temporarily out of print This book will help you learn the basics of computing, and snags of speaker designs. It examines the whys and running applications programs, wiring up a MIDI system wherefores so that the reader can understand the PREAMPLIFIER AND FILTER CIRCUITS and using the system to good effect, in fact just about principles involved and so make an informed choice of R. A. Penfold everything you need to know about hardware and the design, or even design loudspeaker enclosures for him - This book provides circuits and background information programs, with no previous knowledge of computing or herself. Crossover units are also explained, the for a range of preamplifiers, plus tone controls, filters, needed or assumed. This book will help you to choose various types, how they work, the distortions they mixers, etc. The use of modern low noise operational the right components for a system to suit your personal produce and how to avoid them. Finally there is a amplifiers and a specialist high performance audio needs, and equip you to exploit that system fully step-by-step description of the construction of the preamplifier i.e. results in circuits that have excellent 174 pages f» JT. HTT.?- f 1 Ii>J £8.95 Kapellmeister loudspeaker enclosure. performance, but which are still quite simple. All the 148 pages MT! ETTW. f.f TiEETl £3.99 circuits featured can be built at quite low cost (just ELECTRONIC PROJECTS FOR GUITAR a few pounds in most cases). The preamplifier cir- R. A. Penfold cuits featured include; Microphone preamplifiers (low This book contains a collection of guitar effects and ACOUSTIC FEEDBACK - HOW TO AVOID IT impedance, high impedance, and crystal). Magnetic some general purpose effects units, many of which are V. Capel cartridge pick-up preamplifiers with R.I.A.A. equalisa- suitable for beginners to project building. An introduc- Feedback is the bane of all public address systems. tion. Crystal/ceramic pick-up preamplifier. Guitar pick-up tory chapter gives guidance on construction. While feedback cannot be completely eliminated, many preamplifier. Tape head preamplifier (for use with com- Each project has an introduction, an explanation of things can be done to reduce it to a level at which it is pact cassette systems). how it works, a circuit diagram, complete instructions no longer a problem. # Other circuits include: Audio limiter to prevent over- on stripboard layout and assembly, as well as notes Much of the trouble is often the hall itself, not loading of power amplifiers. Passive tone controls. on setting up and using the units. Contents include; the equipment, but there is a simple and practical Active tone controls. PA filters (highpass and low- Guitar tuner; Guitar preamplifier; Guitar headphone way of greatly improving acoustics. Some microphones pass"). Scratch and rumble filters. Loudness filter. Audio amplifier; Soft distortion unit; Compressor; Envelope are prone to feedback while others are not. Certain mixers. Volume and balance controls. waa waa; Phaser; Dual tracking effects unit; Noise loudspeaker systems are much better than others, and 92 pages J M U«!. M :| £4,99 gate/expander; Treble booster; Dynamic treble booster; the way the units are positioned c^n produce a reduced Envelope modifier; Tremelo unit; Dl box. feedback. All these matters are fully explored as well as COMPUTERS AND MUSIC - AN INTRODUCTION 110 pages Temporarily out of print electronic aids such as equalizers, frequency-shifters R. A. Penfold and notch filters. Computers are playing an increasingly important part in HIGH POWER AUDIO AMPLIFIER CONSTRUCTION The special requirements of live group concerts are the world of music, and the days when computerised R. A Penfold considered, and also the related problem of instability music was strictly for the fanatical few are long gone. Practical construction details of how to build a num- that is sometimes encountered with large set-ups. We If you are more used to the black and white keys of a ber of audio power amplifiers ranging from about 50 even take a look at some unsuccessful attempts to cure synth keyboard than the QWERTY keyboard of a com- to 300/400 watts r.m.s. includes MOSFET and bipolar feedback so as to save readers wasted time and effort puter, you may be understandably confused by the jar- transistor designs. duplicating them. gon and terminology bandied about by computer buffs. 96 pages ' £3.99 910 Everyday Practical Electronics, December 1998 Tte®ir^ Paiftai gunidl SCROGGIE'S FOUNDATIONS OF WIRELESS to help the engineer when designing, developing, evaluat- Memory; Binary and hexadecimal; Addressing; Discrete AND ELECTRONICS - ELEVENTH EDITION ing, fault finding and repairing electronic circuits. The logic; Microprocessor action; I/O control; CRT control; S. W. Amos and Roger Amos result is this handy workmate volume: a memory aid, Dynamic RAM; Fault finding digital systems; Dual trace Scroggie's Foundations is a classic text for anyone work- tutor and reference source which is recommended to all oscilloscope; IC replacement. ing with electronics, who needs to know the art and craft electronics engineers, students and technicians. 274 pages £18.99 of the subject. It covers both the theory and practical Have you ever wished for a concise and comprehen- aspects of a huge range of topics from valve and tube sive guide to electronics concepts and rules of thumb? AN INTRODUCTION TO LIGHT IN ELECTRONICS technology,t and the application of cathode ray tubes Have you ever been unable to source a component, or F. A. Wilson to radar, to* digital tape systems and optical recording choose between two alternatives for a particular applica- This book is not for the expert but neither is it for the techniques. tion? How much time do you spend searching for basic completely uninitiated. It is assumed the reader has some Since Foundations of Wireless was first published over facts or manufacturer's specifications? This book is the basic knowledge of electronics. After dealing with sub- 60 years ago, it has helped many thousands of readers to answer, it covers resistors, capacitors, inductors, semicon- jects like Fundamamentals, Waves and Particles and The become familiar with the principles of radio and elec- ductors, logic circuits, EMC, audio, electronics and music, Nature of Light such things as Emitters, Detectors and tronics. The original author Sowerby was succeeded by telephones, electronics in lighting, thermal considerations, Displays are discussed. Chapter 7 details four different Scroggie in the 1940s, whose name became synonymous connections, reference data. l types of Lasers before concluding with a chapter on Fibre with this classic primer for practitioners and students 158 pages l'»J7;f-!T?.V-l |:*Tri £12.99 alike. Stan Amos, one of the fathers of modern electronics t Optics. and the author of many well-known books in the area, 161 pages pTrHTgyrereEa £4.95 took over the revision of this book in the 1980s and it is PRACTICAL ELECTRONIC FAULT FINDING AND UNDERSTANDING DIGITAL TECHNOLOGY he, with his son, who have produced this latest version. TROUBLESHOOTING F. A. Wilson C.G.I.A., C.Eng., FLE E., F.I. Mgt. 400 pages £19.99 Robin Pain This book examines what digital technology has to offer ELECTRONICS MADE SIMPLE This is not a book of theory. It is a book of practical and then considers its arithmetic and how it can be ar- Ian Sinclair tips, hints, and rules of thumb, all of which will equip the ranged for making decisions in so many processes. It then Assuming no prior knowledge, Electronics Made Simple reader to tackle any job. You may be an engineer or tech- looks at the part digital has to play in the ever expanding presents an outline of modern electronics with an em- nician in search of information and guidance, a college Information Technology, especially in modern transmis- phasis on understanding how systems work rather than student, a hobbyist building a project from a magazine, or sion systems and television. It avoids getting deeply in- on details of circuit diagrams and calculations. It is ideal simply a keen self-taught amateur who is interested in volved in mathematics. for students on a range of courses in electronics, includ- electronic fault finding but finds books on the subject too Various chapters cover: Digital Arithmetic, Electronic ing GCSE, C&G and GNVQ, and for students of other mathematical or specialized. Logic, Conversions between Analogue and Digital Struc- subjects who will be using electronic instruments and The book covers: Basics Voltage, current and resis- tures, Transmission Systems. Several Appendices explain methods. tance; Capacitance, inductance and impedance; Diodes some of the concepts more fully and a glossary of terms Contents: waves and pulses, passive components, and transistors; Op-amps and negative feedback; Fault is included. active components and ICs, linear circuits, block and finding - Analogue fault finding. Digital fault finding; 183 pages £4.95 circuit diagrams, how radio works, disc and tape record- ing, elements of TV and radar, digital signals, gating and logic circuits, counting and correcting, microprocessors, calculators and computers, miscellaneous systems. Page 199 (large format) ItTT:rTT7nTi: I £12.99 TRANSISTOR DATA TABLES Hans-Giinther Steidle ELECTRONIC PROJECT BUILDING FOR BEGINNERS Most of the projects can be simply screwed together, The tables in this book contain information about the R. A. Penfold by following the layout diagrams, in a matter of minutes package shape, pin connections and basic electrical data This book is for complete beginners to electronic project and readily unscrewed if desired to make new circuits. for each of the many thousands of transistors listed. The building. It provides a complete introduction to the practi- A theoretical circuit diagram is also included with each data includes maximum reverse voltage, forward current cal side of this fascinating hobby, including: project to help broaden the constructor's knowledge. and power dissipation, current gain and forward transad- Component identification, and buying the right parts; The projects included in this book cover a wide range mittance and resistance, cut-off frequency and details of resistor colour codes, capacitor value markings, etc; of interests under the chapter headings: Connections and applications. advice on buying the right tools for the job; soldering; Components, Sound and Music, Entertainment, Security A book of this size is of necessity restricted in its scope, making easy work of the hard wiring; construction Devices, Communication, Test and Measuring. and the individual transistor types cannot therefore be methods, including stripboard, custom printed circuit 163 pages £4.95 described in the sort of detail that maybe found in some boards, plain matrix boards, surface mount boards and larger and considerably more expensive data books. How- wire-wrapping; finishing off, and adding panel labels; ever, the list of manufacturers' addresses will make it getting "problem" projects to work, including simple 30 SIMPLE IC TERMINAL BLOCK PROJECTS easier for the prospective user to obtain further informa- methods of fault-finding. R. Bebbington tion, if necessary. In fact everything you need to know in order to get Follow on from BP378 using ICs. started in this absorbing and creative hobby. 117 pages Lists over 8,000 different transistors, including f.e.t.s. 135 pages M:T^Tr?3 £4.95 Order code BP379 £4.99 MORE ADVANCED USES 45 SIMPLE ELECTRONIC TERMINAL BLOCK HOW TO DESIGN AND MAKE YOUR OWN P.C.B.S OF THE MULTIMETER PROJECTS R. A. Penfold R. A. Penfold R. Bebbington Deals with the simple methods of copying printed cir- This book is primarily Contains 45 easy-to-build electronic projects that can be cuit board designs from magazines and books and covers intended as a follow-up to constructed, by an absolute beginner, on terminal blocks all aspects of simple p.c.b. construction including photo- BP239, (see below), and using only a screwdriver and other simple hand tools. No graphic methods and designing your own p.c.b.s. should also be of value soldering is needed. Order code BP121 £3.99 to anyone who already understands the basics of voltage testing and simple component testing. BOOK ORDERING DETAILS By using the techniques described in Chapter 1 Our postage price is the same no matter how many books you order, just add £1.50 to you can test and analyse your total order for postage and packing (overseas readers add £3 for countries in the the performance of a range of components with EEC, or add £6 for all countries outside the EEC, surface mail postage) and send a PO, just a multimeter (plus a cheque, international money order (£ sterling only) made payable to Direct Book Serv- very few inexpensive com- ponents in some cases). ice or credit card details, Visa or Mastercard - minimum credit card order is £5 - to: Some useful quick check DIRECT BOOK SERVICE, 33 GRAVEL HILL, MERLEY, WIMBORNE, DORSET BH21 1RW methods are also covered. While a multimeter is supremely versatile, it does have (mail order only). its limitations. The simple add-ons described in Chapter 2 Books are normally sent within seven days of receipt of order but please allow a extended the capabilities of a multimeter to make it even more useful. maximum of 28 days for delivery - more for overseas orders. Please check price and 84 pages £2.95 availability (see latest issue of Everyday Practical Electronics) before ordering from old ELECTRONIC TEST EQUIPMENT HANDBOOK lists. Steve Money For a further selection of books see the next two issues of EPE. The principles of operation of the various types of test instrument are explained in simple terms with a minimum DIRECT BOOK SERVICE IS A DIVISION OF WIMBORNE PUBLISHING LTD. Tel 01202 881749 of mathematical analysis. The book covers analogue and Fax 01202 841692. Due to the cost we cannot reply to overseas orders or queries by Fax. digital meters, bridges, oscilloscopes, signal generators, counters, timers and frequency measurement. The practi- E-mail:dbs@epemag. wimborne.co.uk cal uses of the instruments are also examined. Everything from Oscillators, through R, C & L measure- ments (and much more) to Waveform Generators and testing Zeners. BOOK ORDER FORM 206 pages £8.95 Full name: GETTING THE MOST FROM YOUR MULTIMETER R. A. Penfold Address: .. This book is primarily aimed at beginners and those of limited experience of electronics. Chapter 1 covers the basics of analogue and digital multimeters, discussing the relative merits and the Itmitations of the two types. In Chapter 2 various methods of component checking are Post code: Telephone No; described, including tests for transistors, thyristors, resis- tors, capacitors and diodes. Circuit testing is covered in Signature: Chapter 3, with subjects such as voltage, current and con- tinuity checks being discussed. In the main little or no previous* knowledge or ex- I I I enclose cheque/PO payable to WIMBORNE PUBLISHING LTD for £ perience is assumed. Using these simple component and circuit testing techniques the reader should be able to I I Please charge my Visa/Mastercard £ Card expiry date . confidently tackle servicing of most electronic projects. 96 pages £2.95 Card Number NEWNES ELECTRONICS TOOLKIT- SECOND EDITION Geoff Phillips Please send book order codes: The author has used his 30 years experience in industry to draw together the basic information that is constantly demanded. Facts, formulae, data and charts are presented _Pleasecontinue on separate_sheet_o( gaper i(_necessary_ .la I Everyday Practical Electronics, December 1998 911 BABANI BOOKS We now supply all the books published by Bernard Banani (Publishing) Our customers tell us they appreciate our speedy service and low Ltd, We have always supplied a selected list of Babani books and you will postage charge and they would like to be able to purchase all the books find many of them described on the previous pages or the next two issues from us and thus keep the postage charge to an absolute minimum (1.50p of Everyday Practical Electronics (all books with a BP prefix to the order for UK p&p no matter how many books you buy). We are pleased to be code are Babani books). Many readers have asked us to also supply various able to respond; we are now able to meet all your requirements for other Babani books, which have a reputation for value for money. Babani books - if it's in print we can supply it. Code Title Price Code Title Price Cbtte Price BP36 50 Circuits Using Germanium, Silicon and Zener BP326 An Introduction to Satellite Communications £5.95 BP398 Sage instant Accounting Explained £5.95 Diodes £1.95 BP327 DOS One Step at a Time (covers Version 6.2) £499 8P399 Windows '95 One Step at a Time £4.95 BP37 50 Projects using Relays, SCRs and TRIACs £2.95 BP328 Sage Explained £5.95 BP403 The Internet and World Wide Web Explained £5.95 BP44 IC 555 Projects £3.99 BP329 Electronic Music Learning Projects £4.95 BP404 How to Create Pages for the Web Using HTML £5.99 BP76 Power Supply Projects £3.99 BP331 A Beginners Guide to MIDI £4.95 BP405 MS Works for Windows 95 explained £5 95 BP125 25 Simple Amdteur Band Aerials £1.95 BP334 Magic Electronics Projects £4.95 BP406 MS-Word 95 Explained £6.99 BP132 25 Simple SW Broadcast Band Aerials £1.95 BP337 A Concise Users Guide to Lotus 1 -2-3 BP 144 Further Practical Electronics Calculations for Windows £5.95 BP407 Excel 95 Explained £699 & Formulae £4.95 BP341 MS-DOS Explained (covers V6.2) £6.99 BP408 Access 95 - One Step at a Time £5.99 BP145 25 Simple Tropical and MW Band Aerials £1.75 BP345 Getting Started in Practical Electronics £499 BP409 MS Office 95 One Step at a Time £6.99 BP182 MIDI Projects £2.95 BP346 Programming in Visiual BASIC for Windows £595 BP410 35 Opto-Display Terminal Block Projects £499 BP184 An Introduction to 68000 Assembly Language £2.95 BP349 Practical Opto-Electronic Projects £4.95 BP412 A Practical Approach to Excel for Windows 95 £4.99 BP192 More Advanced Power Supply Projects £2.95 BP350 Electronic Board Games £4.95 BP415 Using Netscape on the Internet £6.99 BP258 Learning to Program in C £4.95 BP352 Excel 5 Explained £595 BP416 Practical Alarm Projects £4.99 BP259 A Concise Introduction to UNIX £4.95 BP354 Word 6 for Windows Explained £5 95 BP417 Explaining Microsoft Publisher for Windows 95 £5.99 BP355 A Guide to the World's Radio Stations £699 BP261 A Concise Introduction to Lotus 1-2-3 (1995/6 Edition) £595 BP418 Word 95 Assistant (Revised Edition) £3.95 BP362 Access One Step at a Time £4.95 BP419 Using Microsoft Explorer on the Internet £699 BP262 A Concise Introduction to WordPerfect BP363 Practical Electronic Music Projects £4 95 BP420 E-Mail on the Internet £6.99 (Revised Edition) £3.95 BP367 Electronic Projects for the Garden £4.95 BP421 Windows 95 Assistant £6 99 BP273 Practical Electronic Sensors £4.99 BP370 The Superhet Radio Handbook £4.95 BP422 Essentials of Computer Security £599 BP275 Simple Short Wave Receiver Construction £3.95 BP373 An Introduction to Networks for PC and BP424 Microsoft Exchange for Business and Home Use £6.99 BP281 An Introduction to UHF/VHF for Radio Amateurs £4.99 Mac Users £5.95 BP425 Microsoft Internet Explorer Assistant £5.99 BP284 Programming in QuickBASIC (revised edition) £5.99 BP375 The Novice Radio Amateurs Examination BP426 MS Office 97 Explained £699 BP292 Public Address Loudspeaker Systems £4.99 Handbook £495 BP427 Netscape Internet Navigator Assistant £5 99 BP293 An Introduction to Radio Wave Propagation £3.95 BP380 Advanced Projects For The Electric Guitar £4.99 BP428 MS Word 97 Explained £699 BP301 Antennas for VHF .and UHF £4.95 BP383 Understanding the Mathematics of Electronics £599 BP429 MS Excel 97 Explained £699 BP309 Preamplifier and Filter Circuits £4.99 BP387 Windows One Step at a Time £4.95 BP311 An introduction to Scanners and Scanning £4.99 BP388 Why Not Personalise Your PC £4 99 BP430 MS Access 97 - One Step at a Time £599 BP312 An Introduction to Microwaves £3.95 BP389 Power Point for Windows Explained £5.95 BP432 Simple Sensor Terminal Block Projects £499 BP315 An introduction to the Electromagnetic Wave £4.95 BP390 An Introduction to the World Wide Web BP434 PC Hardware Assistant £699 BP316 Practical Electronic Design Data £5.99 for PC and Mac Users £6.99 BP435 Programming in C + + £6 99 BP317 Practical Electronic Timing £4.95 BP320 Electronic Projects for Your PC £3.99 BP324 The Art of Soldering £3.99 IF NO PRICE IS SHOWN THE BOOK IS OUT OF PRINT (O.O.R) BP325 A Concise Users Guide to Windows 3.1 £4.95 SEE PREVIOUS PAGE FOR FULL ORDERING DETAILS PROJECT TITLE Order Code Cost MIDI Pedal ■'TV*:LI 938 £7.78 Club Vote Totaliser 939 £6.05 PIC-DATS Development System (double-sided p.l.h.) 940 £9.90 PCB SCIWIC6 EPE HiFi Valve Amplifier - Printed circuit boards for certain EPE constructional projects are available from the Phase splitter 941 £6.71 PCB Service, see list. These are fabricated in glass fibre, and are fully drilled and PIC-DATS 4 -channel Light Chaser 942 £7.90 roller tinned. All prices include VAT and postage and packing. Add £1 per board HV Capacitor Reformer IHTVIC 943 £5,60 for airmail outside of Europe. Remittances should be sent to The PCB Service, Ramp Generator Everyday Practical Electronics, Allen House, East Borough, Wimborne, Dorset BH21 1PF. Tel: 01202 881749; Fax 01202 841692 (NOTE, we cannot reply to Logic Board (double-sided p.t.h.) & Analogue orders or queries by Fax); E-mail: [email protected] . Cheques board (pair) 944/5 £32.00 should be crossed and made payable to Everyday Practical Electronics (Payment Automatic Curtain Winder 946 £6.75 in £ sterling only). Windicator 947 £4.10 NOTE: While 95% of our boards are held in stock and are dispatched within Microcontrolled 3-Digit Timer 933 £6.61 seven days of receipt of order, please allow a maximum of 28 days for Personal Practice Amplifier 950 £6.09 delivery - overseas readers allow extra If ordered by surface mail. Back numbers or photostats of articles are available if required - see the Low-Range Ohmmeter Adaptor ■.-idaih-L* 926 £5.55 Back Issues page for details. Simple Theremin 952 £6.68 Please check price and availability in the latest issue. Vandata - Boot Control Unit 953 £10.52 Boards can only be supplied on a payment with order basis. Display Unit 954 £6.61 Sound Switch 915 £6.55 Multiple Project PCB 932 £3.00 Audio Sinewave Generator Special KNOCK DOWN SALE oi pcbs. Treble Booster We have a few p.c.b.s left from past projects these are being Infra-Red Controller/Alarm (2 boards required) offered at the knock down price of £2.00 each - no matter what Capacitor Check 955 £5.76 size they are (some of these boards are worth over £12.00 Ginormous VU Meter 956 £9.31 each) while stocks last. This price includes Multiple Project PCB ■/>!'*:LM 932 £3.00 Video Enhancer - Current Tracer - VAT and UK post - overseas orders please Distortion Effects Unit add 50p postage (or £1 per board for airmail Digital Delay Line 958 £8.04 postage). 50Hz Field Meter 959 £8.32 Bike Odometer (pair of boards), 836/7; 1W Stereo Temperature Warning Alarm (Teach-in '96) 960 £6.15 Amplifier, 851; Visual Doorbell, 863: EPE SounDAC PC Sound Board, 868; Microprocessor SmartSwitch, 881; Stereo "Cordless" Headphones Print Timer, 874; Stereo HiFi Controller - Power Supply, 886 - Main Transmitter 961 £8.04 Board, 887 - Expansion/Display Boards, (pair) 888; Dancing Fountains - Receiver 962 £7.66 Filter, 891 - PC-Compatible Interface (double-sided), 892; Seismograph - • EPE Met Office - Sensor/Rainfall/Vane 963/965 £11.33 PC-Compatible Interface (double-sided), 898 - Clock/Mixer, 897; Audio Spiral transparency free with above p.c.b. Auxiplexer - Control Board, 903 - Receiver, 904; Power Controller, 905; Light-Operated Switch 966 £6.37 1000V/500V Insulation Tester, 906; Active Guitar Tone Control, 907; TV Modular Alarm System (Teach-in '96) 967a/b £7.12 Off-er (pair), 908/909; VideP Modules - 1 Simple Fader, 910; Video « EPE Met Office - MT71ET Enhancer, 912; Rodent Repeller, 913; Spacewriter Wand, 921; Video Computer Interface (double-sided) 964 £7.69 Modules - 3 Dynamic Noise Limiter, 919 - System Mains Power Supply, 920: Audio Signal Generator 969 £6.58 The Ultimate Screen Saver, 927; 12V 35W PA Amplifier, 930; «National Mains Signalling Unit, Transmitter and Receiver 970/971 (pr) £9.09 Lottery Predictor, 935. Automatic Camera Panning (Teach-in "96) 972 £6.63 Any of the above for just £2 each inc. VAT and p&p. Printer Sharer 973 £9.93 Back numbers or photostats of articles are available see the Vari-Speed Dice (Teach-in '96) Mid:)! 974 £5.69 Back Issues page for details. ^ain^j2nallin2_Unit^£22^Ca£acitive_PSU_ 975 £6.07 912 Everyday Practical Electronics, December 1998 Order Code Cost PROJECT TITLE Order Code Cost PROJECT TITLE ♦ ♦EPE PIC Tutorial MEEEE ""485 "57795 Multi-Purpose Mini Amplifier iiMiim 976 £6.12 High Current Stabilised Power Supply 979 £6.62 The Handy Thing (Double-Sided) 183 £6.58 Ming Machine Mk III - Sound and Lights 980 £7.39 Lighting-Up Reminder 184 £5.90 Infra-Zapper Transmitter/Receiver ♦ Audio System Remote Controller - PSU 185 £7.05 (Teach-m '96) 981/982 (pr) £8.01 Main Board 186 £8.29 iat Band Converter/B.F.O. "554575" "55755" Simple Metal Detector Hearing Tester 985 £6.87 (Multi-project PCB) 932 £3.00 Event Counter (Teach-ln '96) 986 £8.39 Single or Dual-Tracking Power Supply 187 £7,90 B.F.O. and Bat Band Converter "554575" "55W RC-Meter 188 £7.66 Versatile PIR Detector Alarm 988 £6.76 Security Auto-Light "489" "5840 Mind machine Mk III - Tape Controller 989 £6,70 Stereo Tone Control plus 20W Stereo Amplifier Midi Analyser 992 £6.74 Tone Control 190 £7.78 Countdown Timer (Teach-ln '96) 993 £9.44 20W Amplifier 191 £8.58 Sarah's Light 996 £7.17 • Dice Lott 192 £8.05 Home Telephone Link 997 (pr) £10.72 EPE Mood Changer 193 "57775" *PulStar 998 £6.60 ♦ AT89C2051/1051 Programmer VU Display and Alarm 999 £7.02 Main Board 194 £8,50 Ultra-Fast Frequency Generator Test Board 195 £8.69 and Counter - Oscillator/L.C.D. Driver 994/995 (pr) £12.72 ♦ Reaction Timer Software only Timed NiCad Charger 100 £6.99 ♦ PIC16x84 Toolkit "495" "55755 Single-Station Radio 4 Tuner 101 £7.02 ♦ Greenhouse Computer Twin-Beam Infra-Red Alarm -Transmitter/Receiver 102/103 (pr) £10.50 Control Board 197 £9.08 *Games Compendium 104 £6.09 PSU Board 198 £8.10 Mono "Cordless" Headphones w.vwm 199 £6.59 - Transmitter/Receiver 990/991 (pr) £10.16 Float Charger Component Analyser (double-sided p.t.h.) 105 £12.18 Lighlbulb Saver 202 £3.00 Garden Mole-Ester 106 £6.07 Personal Stereo Amplifier 932 "55705 Mobile Miser 107 £6.36 (Multi-project PCB) Bike Speedo 108 £6.61 ♦ Greenhouse Radio Link 200 £8.32 *PIC-Tock Pendulum Clock 109 £6.31 ♦ PIC Altimeter 201 £8.15 Power Check 110 £6,42 Voice Processor "555" "5748 Analogue Delay/Flanger 111 £7.95 ♦ Digiserv R/C Expander 204 £7.69 Draught Detector 112 £6.22 IR Remote Control Simple Exposure Timer 113 £6.63 Transmitter 205 £3.00 Video Fade-to-White 114 £6.98 Receiver 206 £3.50 Direct Conversion 80m Receiver 116 £7.52 ♦ PIC Tape Measure ■/Hl'MrhB "207" £6.82 Vehicle Alert 117 £6.55 Electronic Thermostat 10MHz Function Generator- Main Board 118 £7.33 T-Stat 208 £4.00 -PSU 119 £5.39 Damp Stat (Next Month) 209 £4.50 Tuneable Scratch Filter "445" "57755 PhizzyB £14.95 » Central Heating Controller 120 £7,85 A-PCB B-CD-ROM C-Prog. Microcontroller Bee (A)(B)(C) each D.C. to D.C. Converters - Negative Supply Generator 122 £5,96 15-Way IR Remote Control - Step-Down Regulator 123 £6.01 Switch Matrix 211 £3.00 - Step-Up Regulator 124 £6.12 15-Way Rec/Decoder 212 £4.00 ♦ PIC Digital/Analogue Tachometer "457" Damp Stat 209 "5545 Stereo Cassette Recorder Handheld Function Generator 213 £4,00 Playback/PSU 128 £7.94 ♦ EPE Mind PICkler 214 £6.30 Record/Erase 129 £9.04 ♦ Fading Christmas Lights 215 £5.16 • Earth Resistivity Meter H.IJILU ^hizz^B l/OBoarc^^^^_^ 216 £3.95 Current Gen. - Amp/Rect. 131/132 (pr) £12 70 i — Theremin MIDI/CV Interface (double-sided p.t.h.) 130 (set) £40,00 Mains Failure Warning 126 £6.77 Pacific Waves "455" £9.00 PsiCom Experimental Controller 137 £6.78 Oil Check Reminder "455" "5745" Video Negative Viewer 135 £6.75 Software programs for EPE projects are available on 3.5 inch PC- Tri-Colour NiCad Checker 138 £6.45 compatible disks or via our Internet site. Those marked with a single Oual-Outpul TENS Unit (plus Free TENS info.) 139 £7.20 asterisk ♦ are all on one disk, order code PIC-DISK1, this disk also * PIC-Agoras - Wheelie Meter 44r *5575 contains the Simple PIC16C84 Programmer (Feb '96). The EPE PIC 418MHz Remote Control - Transmitter 142 £5.36 Tutorial (♦ ♦) files are on their own disk, order code PIC-TUTOR. The - Receiver 143 £6.04 PuppyiPuddle Probe 145 £6.10 disks are obtainable from the EPE PCB Service at £2.75 each (UK) to MIDI Miiatrix - PSU 147 £5.42 cover our admin costs (the software itself is free). Overseas (each): - Interface 148 £5.91 £3.35 surface mail, £4.35 airmail All files can be downloaded free Ouasi-Bell Door Alert 133 £6.59 from our Internet FTP site: ftp://ftp.epemag.wimborne.co.uk. 2M F.M. Receiver 144 £7.69 ♦ PIC-A-Tuner 149 £7,83 Window Closer - Trigger 150 £4,91 - Closer 151 £4.47 Child Minder Protection Zone -Transmitter 153 £6.58 EPE PRINTED CIRCUIT - Receiver 154 £6.42 Pyrotechnic Controller 155 £6.93 ♦ PIC Digilogue Clock 156 £7.39 BOARD SERVICE Narrow Range Thermometer 158 £6,37 Micropower PIR Detector - 1 "455" "55755' Order Code Project Quantity Price Infra-Red Remote Control Repeater (Multi-project P.C.BJ 932 £3.00 Karaoke Echo Unit - Echo Board 159 £6.40 - Mixer Board 160 £6.75 Computer Dual User Interface 161 £6.70 Name ♦ PEsT Scarer 162 £6,60 Variable Bench Power Supply "555" "55755 Universal Input Amplifier 146 £6.55 Address Micropower PIR Detector - 2 Controller 163 £6.72 ♦ PIC-OLO 164 £7.02 mo I "445" "55755 Soldering Iron Controller 157 £6.63 ♦ PIC Noughts & Crosses Game 165 £7.82 I enclose payment of £ (cheque/PO in £ sterling only) to: Micropower PIR Detector - 3 Alarm Disarm/Reset Switch 166 £5.72 Everyday Ironing Safety Device 167 £5.12 EUROCAHO Remote Control Finder 168 £6.32 Practical Electronics Rechargeable Handlamp 169 £6.23 Access (MasterCard) or Visa No. ♦ PIC Water Descaler 170 £6.90 ♦ EPt time Machine "471" "55734' Minimum order for credit cards £5 Auto-Dim Bedlightllight 172 £6.63 Portable 12V PSU/Charger 173 £6.61 Car Immobiliser "475" "57755 Safe and Sound (Security Bleeper)' 179 £7.32 Sudace Thermometer "474" "57754" Disco Lights Flasher 178 £8.30 Signature Card Exp. Date Waa-Waa Pedal (Multi-project PCB) "W "55700 ♦ Virtual Scope - Digital Board 176 £14.49 Please supply name and address of cardholder if different from the address shown Analogue Board (per board) 177 £7.34 ♦ Water Wizard 180 £7.69 NOTE: You can order p.c.b.s via our Internet site on a secure server: Kissometer 181 £7.67 http://www.epemag.wimborne.co.uk Everyday Practical Electronics, December 1998 913 SURFING THE INTERNET NET WORK ALAN WIN STAN LEY ■ ! \ Welcome to this month's Net Work, our column specially example. I found that the use of Macromedia Shockwave did little written for Internet users. One or two changes are taking to present the data behind BT's sales pitch more effectively than a place on the EPE web site, including a new link to our Internet-only web site full of static HTML would have done, only the Shock- edition of EPE Online hosted in the USA (www.epemag.com). We wave-enabled site took far longer to visit and therefore told me less are also improving the "Recent Issues" section of our web site in the time available. Some users may find the images of spinning (www.epemag.wimborne.co.uk) in order to devote one web page motorway signposts captivating, though. per issue. They are accessed at pages which are named after their month and issue, so July 98's issue (the earliest currently avail- Software Selection able in this format) is at the page 0798.htm. The pages should be Although I covered it last month, it's still going on - some ■ available from our web site for about a year. readers are still confusing the addresses of our FTP (File The files for this month's projects are available on the FTP site Transfer Protocol) and World Wide Web sites by typing in FTP at ftp://ftp.epemag.wimborne.co.uk/pub/PlCS/MindPICkler and addresses whilst browsing our web site. They need to en- pub/PICS/xmaslighls. sure they type the complete FTP address, which is (again) ftp://ftp.epemag.wimborne.co.uk. From there, navigate to /pub Plight of the Navigator (the public directory, and the only one of interest) before Microsoft Internet Explorer 4 recently arrived in my office as drilling deeper down to the desired location (for example, our an unwelcome guest preinstalled on a new Dell computer. After PIC files are stored in /pub/PICS). There is also a Mirror delivery, Step One was to disable the Active Desktop which I (copy) of our PIC-relaled files maintained by Thomas Stratford found gimmicky, pointless and irritating. Step Two was to attempt on http;//homepages.mldram.co.uk/~starbug/epepic.htm if you to configure all my Dial-Up Networking connections, and my E- prefer a web style. mail software. Unfortunately things rapidly went downhill, with Several popular FTP programs are available via the Internet and recurrent modem nightmares, crashes and re-boots galore and other the rule is to fetch a shareware version and then buy the one which anomalies. And no 1 haven't got Windows 98 (thanks). works for you. Features to look out for include an automatic "reget" A dozen phone calls to Dell and Microsoft, a new motherboard, a of transfers, which means that if interrupted, the transfer can be new memory, three modems and several on-site visits later, two restored from where it left off, rather than having to fetch the entire technical support reps, suggested that one way of curing problems file again. Also, the ability to store sessions (the configuration, might be to type "ieremove" at the Run line, and thereby de-install URL, passwords and other set-up data) related to particular FTP Microsoft Internet Explorer 4. In the event, we decided to give it up sites is useful. This month I've provided a list of some Internet as a bad job and my shiny new PC had to be shipped back to software tools worth checking. Ireland anyway, and - credit to Dell Computer Corporation - it was Absolute FTP is shareware and is said to boast an Explorer-type collected within five hours of my complaining. interface, drag-and-drop file transfers, reget plus the ability to run Upon its return 1 wasn't surprised to see that Explorer 3 had been simultaneous transfers from multiple FTP sites, bandwidth permit- installed as the default web browser: I would have done the same ting. Try www.vandyke.com. For Macintosh users, Anarchie Pro myself. When I queried this, though, it was suggested that if I (v3.0) is now available from www.shareware.com with enhanced proceeded to re-install Explorer 4, I ought not to use the Active web support, offline browsing and an improved graphical front end. Desktop which has been known to "cause problems." As at today, Terrapin FTP and Terrapin Postbox (E-mail client) are not having the Active Desktop installed may now cause a problem at www.terra-net.com and Cute FTP is available from as well, because my very latest version of Hot Metal Pro 5 requires www.cuteftp.com. I like the looks of Crystal Art Software's - you guessed - the Active Desktop to be enabled if I am to access Crystal FTP (www.casdk.com) which installed and worked all of Hot Metal's features. The only alternative, says Softquad, is to instantly. It has a handy-looking "Quick" button and could be just use Windows 98. the thing for struggling Windows users. Web site maintainers might I guess this will be the pattern of events for the next year or two. also enjoy Crystal SiteUpdater (sic) from the same site. It helps Anyway, just for the record, I am delighted to report that the PC with the publishing, synchronisation and validation of web sites but hasn't missed a beat, and as an anonymous customer I found Dell's hasn't been tested by me. FTPPro98 is an Explorer-style FTP client Customer Service highly commendable. from www.ftppro.com, and Bullet Pro FTP looks particularly attractive at www.bpftp.com. Black Spot FTP Explorer from www.ftpx.com has similar controls to I was soon to find that using version 3 of Explorer created a few Microsoft Windows Explorer which beginners might appreciate, problems of its own, when accessing the web sites of Microsoft and Anawave (noted for its "Websnake" software) offers a and Dell in search of patches and drivers. Both sites use Active W95 FTP client interface called FTP Icon Connection at Server technology. My attempts at navigating around their web www.anawave.com. Another popular Macintosh FTP application is sites repeatedly came to a dead end, because ■ of an error mes- Fetch from www.dartmouth.edu. sage "The object has moved and may be found here". Trying WinZIP (now in version 7) is the totally indispensable Windows to jump "here" caused my session to grind to a frustrating halt; Zip utility for compressing or decompressing files. A handy brow- funnily enough the only way forward was to return fully armed ser add-on means that you can view the contents of zipped files in with Netscape Navigator 4.0. Exactly the same happened with my your browser, without having to unzip them separately. Buy it! CompuServe browser which I resurrected on the new PC. (The More from www.winzip.com. "Zip up the Web" is a W95/ NT latest release of Netscape Navigator is V4.5, by the way: more at freeware utility which (it says here) enables you to zip up and www.browsers.com.) E-mail a collection of web pages without facing the chore of For many experienced PC users, Microsoft Internet Explorer 4 is downloading the text and graphics. It creates a self-executable still one upgrade too many which they can probably quarantine file of the web pages, which you can E-mail onwards. It's at alongside Windows 98. Unfortunately the dependency of some web www.shareware.com. sites on displaying .properly (if at all) only if a certain browser is The above URL's are ready-made for you on the Net Work page used, is as frustrating for users as ever. Let us also not forget the of our web site as usual. I welcome your suggestions for links to myriad of browser plug-ins extolled by some web sites: check- share with fellow readers and you'll receive a credit. E-mail ideas to ing the BT Home Highway web site (www.highway.bt.com), for alantcfepemag.demon.co.uk. 914 Everyday Practical Electronics. December 1998 EVERYDAY I VOLUME 27 INDEX JANUARY 1998 TO DECEMBER 1998 PRACTICAL Pages Issue Pages Issue 1-80 January 473-552 July 81-160 February 553-624 August 161-240 March 625-696 September ELECTRONICS 241-320 April 697-768 October 321-392 May 769-840 November The No 1 Magazine for Electronics & Computer Projects 393-472 June 841-920 December CONSTRUCTIONAL PROJECTS ALARM, SWITCH-ACTIVATED BURGLAR 187 OSCILLOSCOPE, EPE VIRTUAL 55, 135 ALARM, VIBRATION 262 PC CAPACITANCE METER by Robert Penfold 752 ALTIMETER, PIC 652 PC TRANSISTOR TESTER by Robert Penfold 603 AMPLIFIER, PERSONAL STEREO 644 PERSONAL STEREO AMPLIFIER by Robert Penfold 644 AMR 20W STEREO plus STEREO TONE CONTROL 362 PhizzyB COMPUTERS by dive "Max"Maxfield, Alvin Brown and ATMEL AT89C2051/1051 PROGRAMMER by Colin Metkle 432 Alan Winstaniey 808, 888 AUDIO FUNCTION GENERATOR 875 1 - Constructing and testing the main board 808 AUDIO SYSTEM REMOTE CONTROLLER by Mark Skeete 220 2 - Simple Input/Output devices 888 AUTO-LIGHT, SECURITY 346 PIC ALTIMETER by John Becker 652 BATTERY CHARGER, LEAD/ACID 574 PICkler MIND MACHINE 850 BATTERY INDICATOR, LOW 484 PIC TAPE MEASURE by John Becker 778 BURGLAR ALARM, SWITCH-ACTIVATED 187 PIC 16x84 TOOLKIT by John Becker 526, 685 CANCELLING UNIT, NOISE 518 PIEZO-CABLE PROJECTS, EXPERIMENTAL 259 CAPACITANCE METER, PC 752 POWER SUPPLY, SINGLE OR DUAL-TRACKING 254 CHANNEL EXPANDER, DIGISERV R/C 724 PROCESSOR, VOICE 707 CHARGER, FLOAT 574 PROGRAMMER, ATMEL AT89C2051/1051 432 CHRISTMAS LIGHTS, FADING 862 RADIO LINK, GREENHOUSE 680 COMPUTERS, PhizzyB 808, 888 RADIO, SIMPLE M.W. 30 COMPUTER, GREENHOUSE 492,610 R/C CHANNEL EXPANDER ' 724 DAMP-STAT ELECTRONIC THERMOSTAT by Andy FHnd 904 RC-METER by Tony Hart 298 DICE LOTT by John Morton 334 REACTION TIMER by Paul Hacked 456 DIGISERV R/C CHANNEL EXPANDER by Tony Hart 724 RELAY POWER CONTROLLER 799 DISCO LIGHTS FLASHER by Terry de Vaux-Batbirnie 12 RELIABLE INFRA-RED REMOTE CONTROL by Max Horsey 732 EEPROM MICROCONTROLLERS, 8051-BASED 426 REMINDER, LIGHTING-UP 168 EFFECTS PEDAL, WAA-WAA 110 REMOTE CONTROLLER, AUDIO SYSTEM 220 EPE MIND PICkler by Andy FHnd 850 REMOTE REPEATER, IMPROVED INFRA-RED 382 EPE MOOD CHANGER by Andy FHnd 404 ROOM TEMPERATURE THERMOSTAT 800 EPE PIC 16x84 TOOLKIT 526, 685 SAVER, LIGHTBULB 564 EPE VIRTUAL SCOPE by John Becker 55, 135 SCOPE, VIRTUAL, EPE 55, 135 EXPERIMENTAL PIEZO-CABLE PROJECTS by Peter SomerviHe SECURITY AUTO-LIGHT by Terry de Vaux-Baibirnie 346 259, 260, 262 SIGNAL GENERATOR, SINE, SQUARE, TRIANGLE 875 DISTRIBUTED MICROPHONE 260 SHOWER WATER METER 92 VIBRATION ALARM 262 SIMPLE M.W. RADIO Ty/fcYre/T/'e/r/b/a' 30 FADING CHRISTMAS LIGHTS by Bart Trepak 862 SIMPLE METAL DETECTOR by Robert Penfold 248 FLASHER, DISCO 12 SIMPLE SW RECEIVER by Robert Penfold 414 FLOAT CHARGER by Andy FHnd 574 SINGLE OR DUAL-TRACKING POWER SUPPLY by Steve Knight 254 FUNCTION GENERATOR, HANDHELD 875 SOCKET TESTER, MAINS 636 GENERATOR, HANDHELD FUNCTION 875 STEREO AMPLIFIER, PERSONAL 644 GREENHOUSE COMPUTER by Colin Meikle 492,610 STEREO TONE CONTROL plus 20W STEREO AMP by Max Horsey 362 GREENHOUSE RADIO LINK by Colin Meikle 680 SURFACE THERMOMETER by Steve Knight 67 SW RECEIVER, SIMPLE ' 414 HANDHELD FUNCTION GENERATOR by Brian Adkinson 875 SWITCH-ACTIVATED BURGLAR ALARM by Robert Penfold 187 HANDY THING by Bill Mooney 174 IMPROVED INFRA-RED REMOTE REPEATER by Robert Penfold 382 T-STAT ELECTRONIC THERMOSTAT by Andy FHnd 796 INFRA-RED REMOTE CONTROL, 15-WAY 824 TAPE MEASURE, PIC 778 INFRA-RED REMOTE CONTROL, RELIABLE 732 THERMOMETER, SURFACE 67 INFRA-RED REMOTE REPEATER, IMPROVED 382 THERMOSTAT, DAMP-STAT ELECTRONIC 904 THERMOSTAT, T-STAT ELECTRONIC 796 KISSOMETER by William Chester 126 TIME MACHINE UPDATE by John Becker 614 LIGHTBULB SAVER by Bart Trepak 564 TIMER, REACTION 456 LIGHTING-UP REMINDER by Bart Trepak 168 TONE CONTROL, STEREO plus 20W STEREO AMP 362 LIGHTS, FADING CHRISTMAS 862 TOOLKIT, PIC 16x84 526 LIGHTS FLASHER, DISCO 12 TRANSISTOR TESTER, PC 603 LOTTERY PREDICTOR, PERSONAL 334 TRIAC POWER CONTROLLER 796 LOW BATTERY INDICATOR by Andy FHnd 484 VIBRATION ALARM 262 M.W. RADIO, SIMPLE 30 VIRTUAL SCOPE, EPE 55, 135 MAINS SOCKET TESTER by Bart Trepak 636 VOICE PROCESSOR by Terry de Vaux-Baibirnie 707 METAL DETECTOR, SIMPLE 248 WAA-WAA EFFECTS PEDAL by Robert Penfold 110 METER, RC- 298 WATER WIZARD by Andrew Buckmaster and Max Horsey 92 MICROCONTROLLERS, 8051-BASED, EEPROM 426 MIND MACHINE, EPE PICkler 850 15-WAY INFRA-RED REMOTE CONTROL by Max Horsey 824 MOOD CHANGER, EPE 404 20W STEREO AMP plus STEREO TONE CONTROL 362 8051-BASED EEPROM MICROCONTROLLERS by Colin Meikle 426 NOISE CANCELLING UNIT by Robert Penfold 518 GENERAL FEATURES ALTERNATIVE AND FUTURE TECHNOLOGIES - 2 PEAK DCA50 COMPONENT ANALYSER REVIEW by Andy FHnd 536 by dive (call me Max) Maxfield 21 PLEASE TAKE NOTE 48,170,685 BOOK REVIEWS 674 PIC 16x84 Toolkit (July '98) 685 CHIP SPECIAL - HT7630 D.C. PIR CONTROLLER by Andy FHnd 132 Surface Thermometer 170 CROCODILE CLIPS REVIEW by Robert Penfold 672 Time Machine (Nov '97) 48 EASY PCS MAKING by Rod Cooper 740 Universal Input Amplifier (Aug '97) 48 EASY-PC FOR WINDOWS 95 REVIEW by Robert Penfoid 819 STRIPBOARDMAGIC REVIEW by Andy FHnd 199 ELECTRONICS PRINCIPLES 5.0 REVIEW by Robert Penfold 744 USING LM335 AND LM35 TEMPERATURE SENSORSdK/lr?o'x/7/>7r/717 IVEX PCB CAD REVIEW by Robert Penfold 600 USING THE L200CV VOLTAGE REGULATOR by Andy FHnd 538 PATENT YOUR INVENTION by Stephen Arnott 281 Everyday Practical Electronics, December 1998 915 SPECIAL SERIES CIRCUIT SURGERY by Alan Winstanley and Ian Bell 44, 148, 201, 304, Generating Short Pulses with Ripple Counters 542 343, 439, 539, 598, 676, 758, 830, 900 Hot Wire Anemometer 895 Adding and Counting Malaise 304 Isolated Multi-output Power Supply 105 Antex - True Brit 440 L.E.D. Cycle Rear Lamp 747 Beefy Zeners 45 L.E.D.s as Photocells 182 Buffers for Beginners 831 Linear Regulator Performance Monitor 542 Crowbars 45 Logic Gate Tester 818 Current Flow 202 Lossless Current Sensing 895 Desolder Fumes, HASAW and COSHH 441 Lucky Numbers 686 Digital Panel Meters 676 Neon Torch 106 Diode and Resistor Queries 149 Pico Prize Winners! 817 Farnell Comes to Terms 599 Playback Amplifier for Micro-cassettes 687 Farnell's Terms 677 Pneumatic Torque Controller 370 Glow Lamps 677 Power-saving Solenoid Control 273 Going Via RC.B.s 306 Simple IR Remote Checker 371 Ground Down 202 Simple Liquid Crystal Display Tester 105 Hardly a Soft Start 677 Simple NAND Circuits 50 Help with a Humid Hut 307 Simple Thermostat 104 High Current Regulator 148 Single Contact Touch Switch 748 High Voltage Components 440 Soldering Iron "Ready" Indicator 895 Ingenious Neon Torch 540 Traffic Light Simulator 274 K-Maps 343 Typewriter Word Counter 443 Light-dependent Switch 900 Ultra Low-current L.E.D. Flasher 593 Lightly Awoken 539 V.C.O. Continuity Tester 49 Mega Volts 201 Vehicle Reversing Alarm 593 Meter Stiff Resistance 676 Versatile Alarm Extender 594 Microlab 441 12V Lamp Dimmer 49 Mini Stroboscope 598 Null Modems and D-connectors 900 INTERFACE by Robert Penfold 192, 357,506, 670 One in a Million 830 L.C.D. Monitor for your PC 670 Positively Negative 201 PC Ins and Outs 192 Pricey Postage 599 PC printer port register pairs - &H278/9, &H378/9 and &H3BC/D 357 Pull-ups and Relays 900 Serial L.C.D. Remote Monitor for your PC 898 Quick Quiz 44 Simple Transistor Tester 192 Resets Cause Upsets 539 Team Quiz Monitoring via the PC's printer port 506 Ripple of Applause 830 PhizzyB COMPUTERS by dive "Max"Maxfield, Scanning Switch Matrices 439 Alvin Brown and Alan Winstanley 803, 882 Tapped Transformer 202 1 - Introducting PhizzyB and PhizzyB Simulator 803 Teach In '98- Back to Basics 201 2 - Input/output board programming 882 Teach-in Micro Lab- new EPROM 759 PIC TUTORIAL SUPPLEMENT by John Becker Tool Case 830 1 - Introduction and building demo p.c.b. between 200 and 201 Trailing the Light Fantastic 540 2 - Monitoring switches and counting time between 280 and 281 Varta Question to Ask 758 3 - 7-seg l.e.d.s, l.c.d.s and EEPROM memory between 356 and 357 Why no PLCs? 149 Wirewrap Sockets 599 TECHNIQUES - ACTUALLY DOING IT by Robert Penfold Wirewrapping 344 124, 308,419, 582, 749 Zener Diodes 44 How to acquire a good selection of popular components tor your 100 Switches Click into Place 343 workshop 749 How to turn a completed circuit board into a finished project 124 INGENUITY UNLIMITED hosted by Alan Winstanley 49, 104, 181, 273, Power semiconductors and heatsinks 419 370, 442, 541, 593, 686, 747, 817, 895 Socket connections plus semiconductor pinouts and substitutes 582 A.C. Ripple Active Rectifier 443 Using plain matrix board, plus solderless and soldered Alternative T-type Latch 273 breadboards 308 Audio Frequency Doubler 817 Audio Switching Unit 747 TEACH-IN '98 - AN INTRODUCTION TO DIGITAL ELECTRONICS Bi-colour L.E.D. Indicator 274 by Ian Bell, Rob Miles, Or Tony Wilkinson, Alan Winstanley Cheap L.E.D. Blinker 104 34, 114, 206, 286, 373, 446, 508, 584, 661 Courtesy Light Delay 818 3 - Diodes, alternating currents and MOSFETs 34 Current Monitor for Power Supplies 182 4 - Binary numbers; digital logic systems; gates and processing D.C. Fan Equaliser 686 circuits; logic in the real world 114 Daisy-chaining Decoder Chips 106 5 - Logic design aids: Boolean algebra; Karnaugh Maps; Arithmetic Digital Sinewave Generation 442 functions; Encoders and decoders 206 DMM Temperature Probe 182 6 - Sequential Logic; SR-flip-flops; Data Latches; Wire Wrapping; DVM Current Shunt 687 Propagation Delays; Glitches; Building a Quiz Master 286 Electronic Toggle Switch 594 7 - More on Flip-flops 373 Electronic Dice 541 8 - Buses and Counters 446 Enthusiast's Radio 542 9 - Counters and Shifters 508 Fan Failure Monitor 181 10 - More Shift Registers, plus Op.amps 584 Flame Effect 181 11 - Memories and the Computer; Analogue Computers; Digital Foghorn Timing Switch 895 Signal Processing 661 REGULAR EE A TURES EDITORIAL 11, 91, 167, 247, 333, 403, 483, 563, 635, 703, 775, 847 NEW TECHNOLOGY UPDATE by Ian Poo/e 47, 102, 194, 270, 340, 413, INNOVATIONS - NEWS, plus reports by Barry Fox 19, 99, 178, 267, 491, 568, 643, 730, 784, 856 338, 411, 487, 571, 639, 715, 787, 859 READOUT addressed by John Becker x 52, 107, 183, 279, 355, 423, 503, 580, 647, 719, 790, 871 NET WORK - THE INTERNET PAGE surfed by Alan Winstanley SHOPTALK with David Barrington 48, 147, 170, 271, 378, 430, 76, 150, 236, 316, 389, 469, 549, 621, 688, 765, 837, 914 537, 608, 685, 746, 831, 902 SPECIAL OFFERS AND SERVICES ADVERTISERS INDEX 80, 160, 240, 320, 392, 472, 552, 624, EPE CD-ROM No. 1 794, plus cover mounted Disk 696, 768, 840, 920 EPE PIC TUTORIAL SUPPLEMENTS Mar '98 to May '98 BACK ISSUES 28, 145, 204, 284, 324, 425, 505, 596, 678, 763, 874 PASSIVE COMPONENTS, cover mounted booklet (Dec. '98) CD-ROMS FOR ELECTRONICS 54, 134, 196, 276, 352, 444, 500, 578, PIC DATA CHART, GIANT PULL-OUT between pages 40/41 650, 722,814, 892 PRINTED CIRCUIT BOARD SERVICE 75, 156, 234, 314, 388, 468, 548, DIRECT BOOK SERVICE 72, 153, 231, 311, 386, 464, 544, 616, 620, 692, 764, 836,913 689, 760, 832, 909 SPECIAL EAE/ESR READER OFFER (Minicraft Tools) 361, 445 ELECTRONICS VIDEOS 65, 152, 230, 297, 360, 467, 547, 615, 675, 723, 792, 908 916 Everyday Practical Electronics, December 1998 VARIABLE VOLTAGE 5 KVA ISOLATION TRANSFORMER AsSuppression. New Ex-Equipment, Ultra Isolation fully shrouded. Transformer Line Noisewith TRANSFORMERS terminal covers and knock-out cable entries INPUT 220V/240V AC 50/60 OUTPUT 0V-260V Primary 120V/240V. Secondary 120V/240V. Pr Ce P&P 50/60Hz.19cm x H 0 16cm,005pF WeightCapacitance 42 kilos. Size, Price L 37cm £120 x W+ 0PANEL 5KVA 2MOUNTING 5 amp max £33.00' £6.00 VAT. Ex-warehouse. Carriage on request 1KVA 5 amp max £45.25 (£45.83 inc£7.00 VAT) 24V DC SIEMENS CONTACTOR SQUIRES Contacts.Type 3TH8022-0B Screw or 2Din x NO Rail and fixing. 2 x SizeNC 230VH 120 AC x W 10A. 45 0-5KVASHROUDED 2-5 amp max £34.00 (£61 39 inc£6.00 VAT) D 75mm Brand New Price £7.63 incl. P&P and VAT. 240V AC WESTOOL SOLENIODS5 1 KVA 5 amp max £46.25 (£47.00 inc£7.00 VAT) TT2 Mod. 1 Rat. 1 Max stroke /8in. Base mounting MODEL AND CRAFT TOOLS (£62.57 inc VAT) V^in. stroke 5lbs pull approx TT6 Mod. 1 Rat. 1 Max. 2KVA 10 amp max £65.00 £8.50 stroke 1 in Base mounting '^m. stroke I5lbs pull (£86.36 inc VAT) approx SERIES 400 Mod. 1 Rat. 2 Max. stroke A comprehensive range of Miniature Hand and Power Tools 3KVA15 amp max £86.50 £8.50 'Vein. Front mounting Vzin. stroke 15lbs pull approx. and now an extensive range of 5KVA25ampmax £150.00 (+(£111.63 Carriage inc & VAT) Price incl p&p & VAT TT5 £5.88. TT6 £8.81, 10KVA 45 amp max £300.00 (+Carriage & VAT) SERIES 400 £7.64. 6KVA 3 PHASE Star. £205.00 (+ Carnage & VAT) AXIAL COOLING FAN Electronic Components Buy direct from the Importers. Keenest prices n the country 230VLow Noise AC 120mmfan. Price square £7.29 x incl. 38mm P&P 3 andblade VAT. 10 watt featured in a fully illustrated 500VA ISOLATION TRANSFORMER Other voltages and sizes available from stock. New manul surplus "C Core' tropicaiised with top plate Please telephone your enquires. and solder connectionsScreen 0-240V Wt 10.5K. AC. 5-0-100-110-120V & INSTRUMENT CASE 336-page Mail Order Catalogue Size: H 195 x 155 x 135mm Brand19cm Deep.new. ManufacturedRemovable front by andImhof rear L panel 31 x forH easy18 x Price £35.00. Carr. £7,50 (£49 94 incl.) assembly of your components Grey textured finish, COMPREHENSIVE RANGE OF complete with case feet. Price £16.45 ind. P&P and TRANSFORMERS-LT-ISOLATION & AUTO VAT. 2 off £28.20 inclusive. 110V-240V Auto transfer either cased with American socket and DIE CAST ALUMINIUM BOX mains lead or open frame type Available for immediale delivery with internal PCS guides, internal size 265 x 165 x 1999 Issue 50mm deep. Price £9 93 mcl. p&p & VAT. 2 off £17 80 ULTRA VIOLET BLACK LIGHT BLUE ind. FLUORESCENT TUBES 230V AC SYNCHRONOUS GEARED MOTORS 2ft4ft 2040 watt £9.00£14.00 (callers (callers only) only) (£16.45(£10.58 incmc VAT) 65mmBrand xnew W 55m Ovoid x D 35mm.Gearbox 4mm Crouzel dia. shaft type x 10mmmotors. long. H SAME DAY DESPATCH 9in12in 6 8 watt watt £3.96 £4.80 +50p 75p p&p p&p (£5.24(£6.52 inc VAT) 6in 4 watt £3.96 -♦ 50p p&p (£5.24 inc VAT) 206 RPM RPM anti anti cw. cw. £9.99 Depth ind. 40mm. p&p &£11,16 VAT. incl. p&p & VAT 230V AC BALLAST KIT SOLID STATE EHT UNIT For either 6in, 9in or 12in tubes £6.05 + £1 40 p&p Input 230V/240V AC. Output approx 15KV. FREE POST & PACKING (£8.75 inc VAT) Producing 10mm sparK Built-in 10 sec The above Tubes are 35004000 angst (350-400um) deal lor timer. Easily modified for 20 sec. 30 sec delecting security markings, effects lighting & Chemeal apphcatons to continuous. Designed for boiler ignition. Other Wavelengths of UV TUBE available lor Germicidal & Photo Dozens of uses in the field of physics and For your free copy of our catalogue Sensitive applications Please telephone your enquiries electronics, e.g. supplying neon or argon 400 WATT BLACK LIGHT tubes etc Price less case £8.50 + £2.40 p&p write, telephone or fax to: GES Mercury BLUEVapour UV lamp LAMP suitable for (£12.81 inc VAT) NMS. use with a 400W P.F, Ballast. EPROM ERASURE KIT Only £39.95 incl p&p & VAT Build your own EPROM ERASURE for a fraction of RANGE OF XENON FLASHTUBES the price of a made-up unit. Kit of parts less case Squires, 100 London Road, Write/Phone your enquiries includes 12in 8 watt 2537 Angst Tube Ballast unit, pair ofmicroswitch bi-pin leads, and circuitneon £15.00indicator, + £2.00on/off p&p switch, safety Bognor Regis, West Sussex SUPER HY-LIGHT STROBE KIT (£19.98 mc VAT) ApproxDesigned 16 joules forAd|ustable Disco, Theatricalspeed £50.00+ use £3.00etc. p&p (£62.28 inc VAT) WASHING MACHINE WATER PUMP P021 1DD Case and reflector £24.00 + £3.00 p&p (£31.73 inc VAT). Brand new 240V AC fan cooled. Can be used tor a SAE for further details including Hy-Light and varietyincludes of p&p.purposes & VAT Inlet £11.20 1 Van., each outlel or lin.2 fordia. £20.50 Price Industrial Strobe Kits. inclusive EUROCARO Tel: 01243 842424 SERVICE TRADING CO ^55? 57 BRIDGMAN ROAD, CHISWICK, LONDON W4 5BB ■■B Fax: 01243 842525 visa Open TEL: 0181-995 1560 FAX: 0181-995 0549 Ample Monda^Fnda^^ ^^^^CCOUNTCUSTOMERSMIN^RDER^IO^^^^^^^^ce SHERWOOD ELECTRONICS FREE COMPONENTS Buy 10 x £1 Special Packs and choose another one FREE SP1 15 x 5mm Red Leds SP132 2 X TL082 Op amps SP2 12 x 5mm Green Leds SP133 20 X 1N4004 diodes U i T I 0 N A L SP3 12 x 5mm Yellow Leds SP134 15 x 1N4007 diodes C 0 L L C G [ 0 F SP6 15 x Red Leds SP136 3 x BFY50 transistors SP7 12 x Green Leds SP137 4 X W005 1 -SA bridge rectifiers JFCHNOLOGY SP10 100 x 1N4148 diodes SP138 20 x 2-2/63V radial elect, caps. SP11 30 x 1N4001 diodes SP140 3 X W04 1 -SA bridge rectifiers SP12 30 x 1N4002 diodes SP142 2 X Cmos 4017 SP18 20 x BC182 transistors SP143 5 Pairs min. crocodile clips DISTANCE SP20 20 x BC 184 transistors (Red & Black) SP21 20 x BC212 transistors SP144 3 X TIP31A transistors LEARNING COURSES in: SP23 20 x BC549 transistors SP145 6 X ZTX300 transistors SP24 4 x Cmos4001 SP146 10 X 2N3704 transistors SP25 4 x 555 timers SP147 5 X Stripboard 9 stnps x 25 holes Analogue and Digital Electronics SP26 4 x 741 Op.amps SP151 4 X 8mm Red Leds Circuits, Fibres & Opto-Electronics SP28 4 x Cmos4011 SP152 4 X 8mm Green Leds SP29 4 x Cmos4013 SP153 4 X 8mm Yellow Leds Programmable Logic Controllers SP31 4 x Cmos4071 SP154 15 X BC548 transistors SP36 25 x 10/25V radial elect, caps. SP156 3 X Stripboard. 14 strips x Mechanics and Mechanisms SP37 15 x 100/35V radial elect, caps. 27 holes GCSE and BTEC Mathematics SP39 10 x 470/16V radial elect caps. SP160 10 X 2N3904 transistors SP40 15 x BC237 transistors SP161 10 X 2N3906 transistors SP41 20 x Mixed transistors SP165 2 X LF351 Op.amps Courses to suit beginners SP42 200 x Mixed 0-25W C.F. resistors SP167 6 X BC107 transistors SP47 5 x Min. PB switches SP168 6 X BC108 transistors and those wishing to update SP102 20 x 8-pin DIL sockets SP175 20 X 1/63V radial elect, caps. SP103 15 x 14-pin DIL sockets SP177 10 X 1A 20mm quick blow their knowledge and practical skills SP104 15 x 16-pin DIL sockets fuses SP105 5 x 74LS00 SP182 20 X 4-7/63V radial elect, caps. Courses are delivered SP109 15 x BC557 transistors SP183 20 X BC547 transistors as self-contained kits SP111 15 x Assorted polyester caps SP187 15 X BC239 transistors SP112 4 x Cmos4093 SP191 3 X Cmos 4023 No travelling or college attendance SP115 3 x 10mm Red Leds SP192 3 X Cmos 4066 SP116 3 x 10mm Green Leds SP193 20 X BC213 transistors Learning is at your own pace SP118 2 x Cmos4047 SP194 10 X OA90 diodes SP120 3 x 74LS93 SP195 3 X 10mm Yellow Leds v Courses may have SP124 20 x Assorted ceramic disc caps SP197 6 X 20 pin DIL sockets BTEC Certification and Tutoring SP130 100 x Mixed 0-5W C.F. resistors SP198 5 X 24 pin DIL sockets SP131 2 x TL071 Op.amps LL.m_ 1998 Catalogue £1 inc. P&P or For information contact: RESISTOR PAi FREE with first order. NOT Enterprises (Quote ref: EPE) RP3 5 each value-tot P&P £1.25 per order. NO VAT. Barnfield Technology Centre RP7 10 each value-tot RP10 1000 popular valui Orders to: Enterprise Way, Luton LU3 4BU RP4 5 each value-total one Sherwood Electronics, Telephone 01582 569757 • Fax 01582 492928 RP8 10 each value-total' vBWttp 7 Williamson St., Mansfield, RPll 1000 popular values 0-5W Notts. NG19 6TD. Everyday Practical Electronics, December 1998 917 EVERYDAY CLASSIFIED Everyday Practical Electronics reaches twice as many UK readers as any other independent PRACTICAL monthly hobby electronics magazine, our audited sales figures prove it. We have been the leading independent monthly magazine in this market for ELECTRONICS the last thirteen years. If you want your advertisements to be seen by the largest readership at the most economical price our classified and semi-display pages offer the best value. The prepaid rate for semi-display space is £8 ( + VAT) per single column centimetre (minimum 2'5cm). The prepaid rate for classified adverts is 30p (-I-VAT) per word (minimum 12 words). All cheques, postal orders, etc., to be made payable to Everyday Practical Electronics. VAT must be added. Advertisements, together with remittance, should be sent to Everyday Practical Electronics Advertisements, Mill Lodge, Mill Lane, Thorpe-le-Soken, Essex C016 OED. Phone/Fax (01255) 861161. For rates and information on display and classified advertising please contact our Advertisement Manager, Peter Mew as above. RCS VARIABLE VOLTAGE D.C. BENCH POWER SUPPLY Up to 20 volts d.c. at 1 amp continous, 1-5 amps peak, Miscellaneous fully variable from 1 to 20 volts. Twin ^ * Voltage and • m,,^ ^ W inc. Current meters t4* □ VAT PRINTED CIRCUIT BOARDS - QUICK AMATEUR SCIENCE! Electronic plans and for easy read- BhHHhSIH Post C4 SERVICE. Prototype and Production. Artwork kits for amateur scientists - physics, astronomy, out. 240 volt a.c. raised from magazines or draft designs at low rocketry, meteorology, alternative energy and input. Fully smoothed, size 23cmxl4cmx8cm. cost. PCBs also designed from schematics. much more. Send £2.50 (payable to Space- RADIO COMPONENT SPECIALISTS Production assembly also undertaken. For Quest) for current edition of "Amateur 337 WHITEHORSE ROAD, CROYDON details send to P. Agar, Unit 5. East Belfast Science!", our quarterly magazine containing SURREY, CRO 2HS. Tel; 0181-684 1665 Enterprise Park, 308 Albertbridge Road, Belfast. projects, plans and articles. You also receive Lots of transformers, high volt caps, waives, output transformers, speakers, in stock. Phone or send your wants list for quote. BT5 4GX, or phone/fax 01232 738897. a FREE copy of our catalogue. Space- G.C.S.E. ELECTRONIC KITS, at pocket Quest, Byker Business Development Centre. money prices. S.A.E. for FREE catalogue. Albion Row, Newcaslle-upon-Tyne NE6 1LQ ELECTRONIC KITS SIR-KIT Electronics, 52 Severn Road, Clacton, (www.users.globalnet.co.uk/~sqf). CO 15 3RB. RE SOLUTIONS ICEPIC DEVELOPMENT ♦ 88-108MHz FM transmitters from under £5 NEW AND USED COMPUTERS, spares, etc. SYSTEM. "In Circuit Emulator" for PIC Per- ♦ Many educational and hobby electronic at keenest prices, e.g.: 386 min 2MB RAM, sonality modules for 74 and 84 Families. In- kits covering all technical abilities, from 20MB HDD, desktop case, keyboard and cables, cludes Crystal Oscillator Set, Reluctant sale, beginners' circuits to MCU/MPU designs 12in. VGA mono monitor, £55. 486 DX33 min. £800. cost £1,500 new. 0113 225 9405. ♦ Low cost PCB services and equipment 8MB RAM. 120MB HDD, desk top case, key- EPE MINT-LAB AND MICRO-UAB, includes ♦ Send 4x1 st class stamps for catalogue board and cables. I4in. VGA colour monitor. both P.S.U.s and Teach-in 7 manual, £150. 0113 £165. Many other systems available. Whatever 225 9405. DTE MICROSYSTEMS, 112 SHOBNALL ROAD, you need, Phone/Fax 0181 853 3374 for prices. SAMPLE 30 ASSORTED COMPONENTS! BURTON -ON-TRENT. STAFFS DEI 4 2BB VALVE ENTHUSIASTS: Capacitors and other L.E.D.s, resistors, capacitors, new and useful PHONE or FAX; 01283 542229 parts in stock. For free advice/lists please ring, values plus 12 interesting projects. 26p s.a.e.: http:/;www.blinternet.com/~dlemicrosystems Geoff Davies (Radio), Tel. 01788 574774. K.I.A., 1 Regent Road, llkley LS29. TEKTRONIX THS720A, 100MHz, BRAND NEW SINCLAIR SPECTRUM PROTOTYPE PRINTED CIRCUIT b QL PARTS BOARDS one offs and quantities, for details send 500Ms/s sampling, Handheld Digital ZX MICRODRIVES C15. INTERFACE ONE £20, s.a.e. to B, M. Ansbro. 38 Poynings Drive, Hove, Oscilloscope/Multimeter. RS232 comms CARTRIDGES 10 FOR £15, 50 FOR £50. Sussex BN3 8GR, or phone Brighton 883871, fax interface. Hardly used, offers invited. Tel. QL BOARDS 5, 6 &7. POPULATED WITH 01273 706670. 0181 871 3312. I JS ROMS, £30; UNPOPULATED, £12; MICRODRIVES £10 EACH. TOP b BOTTOM CASES £15, MEMBRANES £15. rfHE PC., MAC and QL's "Little Friend" MAC LINK £10 - P.C. LINK £25 - QL LINK £12 EPE NET ADDRESSES CAMBRIDGE Z88 A4 NOTEBOOK COMPUTER AVAILABLE AGAIN £99, RECONDITIONED £60 EPE FTP site; ftp://ftp.epemag.wimborne.co.uk ONLY 1" THICK, 4xAA BATTS. 20 HOURS WORK. LCD SCREEN, 72 Crs, 6 LINES, 32K RAM. EXTRA Access the FTP site by typing the above into your web browser, or by I RAMS b EPROMS, 9 pin D SERIAL PORT. ROM HAS BBC BASIC, W/PROCESSOR, SPREADSHEET, DATA setting up an FTP session using appropriate FTP software, then go BASE, IMP/EXPORT TO PC etc, V52 TERMINAL. W./V. RICHARDSON h CO. into quoted sub-directories: PHONE/FAX 01494 871319 6 RAVENSMEAD, CHALFONT ST PETER. PIC-project source code files: /pub/PICS BUCKS. SL9 ONB. PIC projects each have their own folder; navigate to the correct folder and open BTEC ELECTRONICS it, then fetch all the files contained within. Do not try to download the folder Itself! TECHNICIAN TRAINING EPE text files: /pub/docs GNVQ ADVANCED ENGINEERING (ELECTRONIC) - PART-TIME Basic Soldering Guide: solder.txt HND ELECTRONICS - FULL-TIME EPE TENS Unit user advice: tens.doc and tens.txt B.Eng FOUNDATION - FULL-TIME Ingenuity Unlimited submission guidance: ing unlt.txt Next course commences New readers and subscribers info: epe_info.txt Monday 1st February 1999 Newsgroups or Usenet users advice: usenet.txt FULL PROSPECTUS FROM Ni-Cad discussion: nicadfaq.zip and nicad2.zip LONDON ELECTRONICS COLLEGE UK Sources FAQ: uksource.zip Ensure you set your FTP (Dept ERE) 20 PENYWERN ROAD Writing for EPE advice; write4us.txt software to ASCII transfer EARLS COURT, LONDON SW5 9SU when fetching text files, or TEL: 0171-373 8721 they may be unreadable. On-line readers! Try the new EPE Chat THE BRITISH AMATEUR Note that any file which Zone - a virtually real-time Internet ELECTRONICS CLUB ends in .zip needs un- exists to help electronics enthusidsts by personal "discussion board" in a simple to use zipping before use. Unzip contact and through a quarterly Newsletter. web-based forum! utilities can be downloaded For membership details, Wite to the Secretary: from : Mr. J. F. Davies, 70 Ash Road, Cuddington, http:;7www.epemag.wimborne.co.uk/wwwboard http;//www.winzip.com or Northwich, Cheshire CW8 2PB. Or buy EPE Online: www.epemag.com http://www.pkware.com Space donated by Everyday Practical Electronics 918 Everyday Practical Electronics. December 1998 TRAIN TODAY FOR A BETTER FUTURE Now you can get the skills and qualifications you need for Electrical Contracting & Installation career success with an ICS Home Study Course Leam in Electrical Engineering the comfort of your own home at the pace and times that C&G Basic Electronic Engineering Service Manuals suit you. ICS is the world's largest, most experienced C&G Basic Mechanical Engineering home study school. Over the past 100 years ICS have TV and Video Servicing helped nearly 10 million people to Improve their job Radio and Hi-Fi Servicing prospects. Find out how we can help YOU Post or phone Refrigeration Heating & Air Conditioning Available for most equipment, from the earliest Valve Wireless to the latest Video today for FREE INFORMATION on the course of your Motorcycle Maintenance Recorder, Television, Computer Monitor, Test Equipment, Satellite, all Audio, FREEPHONE 050( 3 581 557 Amateur Radio, etc., etc. If you need a Service Manual give us a call or check out Or write to: International Correspondence Schools, FREEPOSTPOST 882, 8 Elliot Place.Place the full stock list now on our web site. Originals or Photostats supplied as available. CJjrdewaj^kgjark^asjow, G3 8BR Tel. 0500 581 557 or Tel/Fax:Tel/Fax; IrelandIrelai 01 285 7S&.J For your FREE catalogue of Technical Books and repair guides Please send me my Free Information on your Electronics■lectronics Courses.C PLUS full Floppy Disc Index of manuals available send 4 x first class stamps. Mr/Mrs/Ms/Miss | (BLOCK CAPITALS PLEASE) Date of Birth / MAURITRON TECHNICAL SERVICES Address 8 Cherry Tree Road. Chinnor, Oxon, OX9 4QY Postcode Tel: 01844-351694. Fax: 01844-352554. Occupation Tel. No. E-mail: [email protected] Vyodu^andservicwFrom time to time , twe permitIf you otherwoulp carefully prefer not saeened to hear fromorganisations such organisations to wnte to pleaseyoo about tK* bo* □ rwitp rppcnfinao^ 1 B Web site at: http://www.mauritron.co.uk/mauritron/ Professional 88-108MHz FM Broadcasting Kits N. R. BARDWELL LTD (ERE) All Our Kits Include 100 Signal diodes 1N4148 £1.00 200 Asstd. disc ceramic capacitors £1.00 Detailed Instructions with Schematics 75 Rectifier Diodes 1N4001 £1.00 50 Asstd Skel Presets (sm, stand, cermet).. £1.00 High Quality Screen Printed PCBs 50 Rectifier Diodes 1N4007 £1.00 50 Asstd RF chokes (inductors) £1 00 High Quality Components 10 W01 Bridge Rectifiers £1.00 50 Asstd grommets £1 00 410 555741 OpTimer Amps I.C.8 £1.00 80 Asstd solder tags, p/conns. terminals £1 00 Our Product Range Includes 50 Assorted Zener Diodes 400mW £1,00 2410 Asstd crystals - plug in...... £1 00 12 At sorted 7 -segmenl Displays £1.00 8 Asstd cotl formers £1 00 Transmitters from 0.06W to 35W 25 5mm l.e.d.s, red, green or yellow £1.00 20 MiniatureAsstd dii switchesslide switches sp/co £1 00 FM Stereo Coders 25 3mm l.e.d.s, red, green or yellow £1.00 10 Standard slide switches dfVdt £1 00 Audio Compressor Limiters 50 Axial l.e.d.s. 2mcd red Diode Package £1.00 30 Asstd it translormers £1 00 Antennas 25 Asstd. Hgh Brightness l.e.d.s. var cols £1.00 100 Asstd beads (ceramic, teflon hsh spme) £i 00 RF Power Amps 2520 BC182LBC212L TransistOfSTransistors £1£100 00 80 Asstd small stand ofts. ithroughs etc £100 30 BC237 Transistors £1 00 30 TVAsstd coax dil plugs, sockets plastic up to 40 way £1 00 Our Kits Are Also Available 20 BC327 Transistors £100 2010 Small spnng loaded terminals £1 00 Fully Assembled And Tested 30 BC328 Transistors £1 00 40 metres very thin connecting wire, red £1 00 30 BC547 Transistors £100 20 Iki. glass reed switches £1.00 30 BC548 Transistors £1 00 20 Magnetic ear pips with lead and plug £1 00 1W Professional PLL FM TrsnsmKter for Lksncml Use In the UA 30 BC549 Transistors £1 00 100 Any one value ViW 5% cf resistors range M DfLIVFR worn D WWW AND 25 BC557 Transistors £100 1R to 10M £0 45 ACCtPT MAJOR CRtOil CARDS Visit our Website at http;//www.veronica.co.uk 30 BC559BC558 Transistors £100£1 00 ConLicl Us Now For A Free Brochure 20100 2N390450v wkg TransistorsAxial Capacitors 1 nf £1.00£100 Prices include VAT, postage tl .25.31p stamp tpr Lists 100 50v wkg Axial Capacitors 4N7 £1.00 Tel 01274 883434 Fax 01274 428665s Avero'ni'caA . 100 50v wkg sub- miniature Capacitors 33nf... £ 1,00 288 Abbeydale Road. Sheffield S71FL email [email protected] 12 luf 250v encapsulated radial plastic cased Phone (0114) 2552886 Fax (0114)2500589 Unit 5/6 1A Sandbedv Albert Rd Qussnsbury BRADFORD B013 Vl/WpTSV capacitors £1.00 IE-mail nuitif^mwmMiyii i mil 80 Asstd capacitorscapacitors electrolytic-1 nF to 1 pT £1.00£1 00 Website: http: ounrorid.Compuserve.comlwmcpage&BARDWELlS | ©D TECHNICAL INFORMATION SERVICES Midlinbank Farm, Ryelands, Nr. Strathaven, MHO 6RD SUPPUER OF QUALITY USED OPERATOK? 4 SERVICE MANUALS Tel: 01698 883334/884585 Fax: 01698 884825 TEST INSTRUMENTS PHONE NOW FOR YOUR FREE QUOTE <.*■ We have the World's Largest Collection of SERVICE MANUALS Why not join Europe's fastest growing "Information Library Service" Buy ANY Service Manual for £10.00 and return any manual no longer needed for a £5.00 credit Cooke fntcmational Cooke fniernational CALL/WRITE NOW FOR FURTHER DETAILS BogUnit nor Four, Regis, Fordingbridge West Sussex, Site,P022 Barn 0HD, ham. U.K. BognorUnit Four. Regis, Fordtrvgbridge West Sussex, 5ite,P022 Bamham. OHO. U.K Initial joining fee of £65 : Thereafter £20 Yearly Trl (♦44)01241Web. htip2/vw*w.cooke S4S111/2 Fe* (♦44)01243 int com 542457 Tel; (♦44)01243Web: hltpy/svww.cooke-int 545111/2 Fa* (♦44)01243 com 542457 E mail infoOcooke-int.com E mail jnfoCrooke-int.com Join Now: Get your first Manual FREE! Wherever you live in the world, you can FML ELECTRONICS subscribe to ERE or renew on-line via our * KITS AND COMPONENTS FOR CHRISTMAS ^ Secure Server. OLD FAVOURITES - El BARGAIN PACKS STILL AVAILABLE; 100 ASSORTED ELECTROLYTICS NOW ONLY £1 PLEASE SEND SAE FOR FURTHER ERE KIT DETAILS, AND Payment by VISA or Mastercard. 350 ASSORTED RESISTOR PACK STILL £1 BASICPLEASE COMPONENT SPECIFY THE KIT KITS EXAMPLES: THAT INTEREST YOU 80 ASSORTED CAPACITORS InF to 2-2^F £1 KIT TYPE (EPE): DATE FROM Check the "Subscriptions" link on the 2 ASSORTED WIRE PACKS 5 * 5 YARDS £1 KIT 8778 PIC TAPE MEASURE NOV 98 £33 ERE web site. 30 ASSORTED DIL SOCKETS UP TO 40-WAY £1 KIT8796T T STAT TRIAC THERMOSTAT NOV 98 £22 25 ASSORTED TRANSISTORLE D. PACK PACK STILL £1 KIT8796R T-STAT RELAY THERMOSTAT NOV 98 £25 USEFUL DEVELOPMENT PACKS FOR ALL CONSTRUCTORS:STILL £1 KITKIT8824T 8824R 15-WAY15-WAYI I.R.R R R TRANSMITTERRECEIVER NOV 98 £38£25 http://www.epemag.wimborne.co.uk KIT8707 VOICE PROCESSOR OCT 96 £24 0-25W0-25WE12 E12 5*7310*73 VALUES VALUE 10-10M10-10M 730365 RESISTORS £2£3.99 70 KIT8724 DIGISERV R/C CHANNEL EXP, OCT 98 £19 0-25W E24 5*145 VALUE 10-10M 730 RESISTORS £540 REUABLE INFRA-RED REMOTE CONTROL (OCT *) 0-5W E12 5*73 VALUES lOU-lOM 365 RESISTORS £3.70 KIT8732TM MOMENTARY TRANSMITTER MODULE■ £13 0-5W E12 10x73 VALUES 10-10M 730 RESISTORS £6.25 KIT8732TB BEAM-BREAK TRANSMITTER MODULE £11 0-5W E24 5x145 VALUES 10-10M 730 RESISTORS £740 KIT8732TZ 1 TO 4-WAY TRANSMITTER MODULE £15 Internet users! Back Issues, P.C.B.s and reprints RADIAL ELECTROLYTIC CAPACITOR DEVELOPMENT PACK: KIT8732RM MOMENTARY RECEIVER MODULE £15 of articles can be ordered on-line via our Secure lOOpiF,1^. 2M2. 220tiF, 4ji7, 470uF1(HiF 50/100V16V, 10 EACH.22^, 47UFTOTAL 25V/50V. 90 IOORF,£5 99 KIT8732RB BEAM-BREAK RECEIVER MODULE £17 SEMICONDUCTOR DEVELOPMENT PACKS; KIT8732RZ 1 TO 4-WAY RECEIVER MODULE £16 Server, check the "Back Issues" links on our 1N4148GEN PURPOSE SIGNAL DIODE 100 FOR £1 KIT8852 PC CAPACITANCE METER OCT 98 £10 1N914 SI WHISKERLESS SIGNAL DIODES 50 FOR £1 PLEASE ORDERENQUIRE YOUR ABOUT KITS ANY NOW OTHER FOR KITSCHRISTMAS REQUIRED web site. 0A91 GE PT SIGNAL DIODES 115V 50MA 4 FOR £1 PLEASE NOTE THERE IS NO MINIMUM ORDER VALUE BC549/BC559 PACK, 10 EACH TOTAL 20 kx £1 SEE PREVIOUSNEXTtPE FOR MORE FML BARGAINS Payment by Mastercard or VISA. 1*40018,40178,40468,1 *555, 555L, 741. LF351IC 7400 PACK LOGIC PACK 4 TOTAL £1 INLAND UK PSP STILL ONLY[1 PER ORDER NO VAT RADIO COMMUNICATION BARGAINS: PLEASE SEND LARGE SAE FOR FREE COMPONENT LISTS LOW-PASS R.F FILTER FOR C8 OR RADIO HAM USE RETAILS TRADE GOVTAND EDUCATIONAL ORDERS http://www.epemag.wimborne.co.uk AEC LP30 CUT OFF 30MHZ 50 OHM BARGAIN £10 FMLWELCOME ELECTRONICS, CHEQUES OR P.O FREEPOST S WITH ORDER NEA3627. PLEASE TO MORSE KEY PRACTICE SET ONLY £10 BEDALE, NORTH YORKSHIRE. DL8 2BR. Everyday Practical Electronics, December 1998 919 COVERT VIDEO CAMERAS Millions of quality components Black and White Pin Hole Board Cameras at lowest ever prices! with Audio. Cameras in P.I.R., Radios, Plus anything from bankruptcy - theft recovery Clocks, Briefcases etc. Transmitting - frustrated orders - over production etc. Cameras with Receivers (Wireless). Send 45p stamped self addressed label or Cameras as above with colour. envelope for clearance lists. Audio Surveillance Kits and Ready Built Brian J Reed 6 Queensmead Avenue, East Ewell Units, Bug Detector etc. Epsom, Surrey KT17 3EQ Tel: 0181-393 9055 or 07775 945386 A.L. ELECTRONICS Mail order UK only. Please phone 0181 203 0161 for free catalogue. Lists are updated and only 40 are sent out every 2 weeks. This normally ensures that orders can be fulfilled where only a few Fax 0181 201 5359 thousand of an item is available. (Payment is returned if sold out. I do not deal in credit notes). This will sometimes entail a delay of up to New DTI approved Video Transmitters and Receivers (Wireless) eight weeks - but the prices will be worth the wait! Quad speed Toshiba 1/3rd height SCSI cd-rom 1 ^MB 5V*' floppy drive £10 drives £20 each, 6 for £100 12V d.c. 200 r.p.m. geared motor 1 meg. 30-pin parity simms...£3.75 each, 4 for £12 £1.50 each, 10 for £12 4 meg 30-pin parity simms. .. £13 each 4 tor £50 SCSI 2 fast differential hard drives ADVERTISERS INDEX 256k pipeline burst cache £4.50 each 1 Gig £58 512k pipelilne burst cache £9 each 2 Gig £85 Indent 512k video cards £12 each 4 Gig £145 A.L ELECTRONICS 920 Tndent 1 mb VLB video cards £20 each 1 Gigabyte laptop drives. Win. IDE £78 each Internal VGA leads £2.50 each. 10 for £20 N. R. BARDWELL 919 3-device SCSI leads £3 each QUANTITY DISCOUNTS AVAILABLE B.K. ELECTRONICS Cover (iii) IDE leads £2 each PLEASE RING. Hard and floppy drive IDE controller cards £5 We also buy all forms of electronic BRIAN J. REED 920 14,400 internal voice/fax/data modem £15 components, p.s.u's, disk drives etc. BULL ELECTRICAL Cover (ii) 28.800 internal voice/fax/data modem £28 Lists to below address. 3lb mixed component pack £4.95 ALL PRICES INCLUDE V A T COMPELEC 920 Jumbo component pack £10 PLEASE ADD C2 00 pip EXCEPT COOKE INTERNATIONAL 919 250 off mixed capacitors £4.95 ITEMS MARKED ♦ WHICH ARE SOP 250 off i.e. sockets £3.95 SAE FOR BULK BUYING LIST CROWNHILL ASSOCIATES 844 1000 off mixed ceramic caps £7.50* PA YMENT WITH ORDER TO 20 off mixed crystals/fitters £4.95 Dept EE. COMPELEC, DANNELL ELECTRONICS 873 25 off mixed relays £3.50 14 Constable Road. DISPLAY ELECTRONICS 842 Brand new 360k 5V* floppy drive £4.50 St. Ives. Huntingdon, SW to 3Vi" floppy dnve Cambs PE17 6EQ ELECTROMAIL 869 converter leads £1.50* Tel/Fax; 01480 300819 EPT EDUCATIONAL SOFTWARE 858 ESR ELECTRONIC COMPONENTS 846 NEW SPECIAL OFFERS FML ELECTRONICS 919 Amiga genlock peb (uncased) for titling videos it has rales) £2.95 a 23pin D lead to plug into the computer and peb Special offers please check for availability stick of 4 GREENWELD 845 pins for composite video in and out. When no video 42x16mm nicad batteries 171mmxl6m(n dia with red & input is connected the normal computer display .. black leads 4.8v £5.95 shown on the composite video out when the video 5 button cell 6V 280mAh battery with wires (Varta ICS 919 input is added the white areas on the screen are 5x250DK) £2.45 J&N FACTORS 897 fromreplaced the computerby the video image. The peb is powered£19.98 Orbitel 866 battery pack 12v 1 60AH contains 10 sub C WATCH SLIDES ON TV "Liesgang diatv" automatic cells with solder tags (the size most commonly used in JPG ELECTRONICS 920 slide viewer with built in high quality colour tv cordless screwdnvers and drills 22 diax42mm tall) it is camera, composite video output with a BNC plug. In easy to crack open and was manufactured m 1994 LABCENTER ELECTRONICS 870 very good condition with few signs of use. — —wBCI box ..TW/. 190x106x50mm . vwosviinn£8.77 mm with OIWIOeach slots IWor toliuuac 110.50 house a UUJpera peb boxmc the of"U lid14 sensorBoard cameraswith composite all with video512x582 out pixels All need4 4x3.3mm to be contains *—* an edge connector1. (12 way 8mm.r. pilch) • and MAGENTA ELECTRONICS 848/849 housed in your own enclosure and have fragile ex- screw terminals to conhect in wires and 5 slide in cable posed surface mount parts and require 10 to I2vdc 7segmentblanks common anode led display 12mm ..£2£0.45 95 MAPLIN ELECTRONICS Cover (iv) power supply. GaAs FET low leakage current S8873 £12.95 each 47MIR size 60x36x27mm with 6 infra red leds £9 95 10+ 7.95 100+ BC547A transistor 20 for £1 00 MAURITRON 919 (gives the same illumination as a small torch would) SL952 UHF Limiting amplifier LC 16 surface mountiounting MR size 39x38x23mm spy £50.00+vatcamera with = £58.7540 a fixed package with data sheet. £1 95 NATIONAL COLLEGE OF TECH 917 focus pin hole lens for hiding behind a very small DC-DC converter Reliability model V12P5 12v m 5v riole £57+vat = £66 98 each200ma or out pack 300v of 10input £39.50 to output Isolation with data £4 95 NUMBER ONE SYSTEMS 845 this40MC gives size a 39x38x28mmmuch clearer camerapicture thanfor Cwith mount the small lens Airpax27ohm 68mmA82903-C dia body large 6.3mm stepping shah motor 14v 7 5' step PICO TECHNOLOGY 881/903 lenses £68.79 Standard C mount lens F1.6 16mm for 40MC Polyester capacitors box.£8.95 type 22.5mmor £200.00 lead for apitch box 0of 9uf 30 £26 43+vat = £31.06 250vdc 18p each Up 100+ 9p 1000^ luf 250Vdc 20p CUASAR ELECTRONICS 903 Waterproof camera with stylish tilt & each.ISp 100 + .10P 1000 + QUICKROUTE SYSTEMS 857 swivel10+ £89 32case +vat = £104£92.76 95 + vat = £109.00 or Polypropylene luf 400vdc (Wima MKP10) 27 5mm pitch DTA30 Hand held transistor analyser it tells you 32x29x 17mm case 75p each 60p 100 + RADIO-TECH 903 which lead is the base, the collector and emitter and 2.2ufPhilips 40v 123 40p series each. solid 25p aluminium 100 + axial leads 33uf lOv & if it is NPN or PNP or faulty. HMA20 hand held Solid carbon resistors very low inductance ideal (or RF SEETRAX CAE 873 MOSFET analyser identifies gate dram and source circuits 27ohm 2W, 68ohm 2W 25p each 15p each 100 +. and if P or N channel DTA30 & HMA20 we have a range of 0 25w 0.5w iw and 2w solid carbon SERVICE TRADING CO 917 DCA50 component analyser with led readout£38.34 eachiden- resistors, please send SAE for list tifies transistors mosfets diodes & LEDs lead 2MohmMX 180 Digital200mA multimetertransistor 17Hfe ranges 9v andlOOOvdc 1.5v 750vacbattery SHERWOOD ELECTRONICS 917 Speakerconnections cabinets 2 way speaker systems£69 with 95 test £9.95 motorola tweeters Hand held ultrasonic remote control £3,95 SQUIRES 917 15' 12- 8" CV2486 gas relay 30x10mm dia with 3 wire terminals will power rating 250WRMS 175WRMS 10OWRMS also work as a neon light STEWART OF READING 844 impedance 8ohm 8ohm 8ohm Varbatim R300NH Streamer...20p tape commonlyeach or £8.50 used per on 100 nc freq range 40hz-20khz 45hz-20khz 60hz-20khz machines and printing presses etc. it looks like a normal SUMA DESIGNS 894 sen$itivity(1W'1M) 97dB 94dB 9208 cassette with a slot cut out of the lop £4.95 each (£3.75 weightsize «i mm 500x720x340450x640x345 315x460x230 100 + ) TECHNICAL INFORMATION SERVICES....919 price each lor black 21 1kg 16.8kg 7 4kg Heatsink compound tube £0.95 vinyl coating £139.95 £99 99 £54 94 pmHV3-2405-E5 OIL package 5-24v 50mA regulator£3.49 ic each18-264vac (100 +input 2.25) 8 VANN DRAPER ELECTRONICS 869 grey fell coating £159.97" £119.97" £64 99 (=not normaly in stock allow 1 week for delivery) All productsp , advertised are, newrMn ande -n-. unused 7ilur unless t/c r.^.other- VERONICA KITS 919 Power amplifiers 19" rack mount with gam controls rechar ab,eS-LPiTS t>at,er,eS , . f STA150 2xl60Wrms (4ohm load) 14kg £202 11 . ^ 'f' L 9 ' capacitors, tools IS iSm load) 1*1 « P P (0,0*3 trow k Sco,„sh lEDs 3mm or 5mm red orlreen 7B each .allow Hl9hl^ Wand SIsle ol Man, Isle ol Wight ADVERTISEMENT MANAGER: PETER J. MEW ,, h Cabl THE RENOWED MXF SERIES OF POWER AMPLIFIERS FOUR MODELS:- MXF200 ( 100W + 100W ) MXF400 (200W + 200W) MXF600 (300W + 300W) MXF900 (450W + 450W) PLEASE NOTE:- POWER RATINGS ALL POWER RATINGS ARE R.M.S. INTO 4 OHMS, WITH BOTH CHANNELS DRIVEN QUOTED ARE IN WATTS R.M.S. FOR FEATURES: * Independent power supplies with two toroidal transformers * Twin L.E.D. Vu Meters EACH INDIVIDUAL CABINET. * Level controls * Illuminated on/off switch * Jack/XLR inputs * Speakon outputs * Standard 775mV ALL ENCLOSURES ARE 8 OHM. inputs * Open and short circuit proof * Latest Mos-Fets lor stress tree power delivery into virtually any I—15=15 inch speaker load * High slew rate * Very low distortion * Aluminium cases * MXF600 & MXF900 tan cooled with D C. ^ '—12=12 inch speaker loudspeaker and thermal proteclion. ibl FC15 300 WATTS Freq Range 35Hz 20KFIz, Sens 101dB, Size H695 W502 D415mm USED THE WORLD OVER IN CLUBS, PUBS, CINEMAS, DISCOS ETC PRICE:- £299.00 per pair ibl FC12-300 WATTS Freq Range 45Hz-20KHz, Sens 96dB, Size H600 W405 D300mm MXF200 W19" Dll" HSi" (2U) PRICE;- £249.00 per pair SIZES MXF400 W19" D12" H5T" (3U) ibl FC12-200 WATTS Freq Range 40Hz-20KHz, Sens 97dB, Size H600 W405 D300mm MXF600 W19" D13" H5V (3U) PRICE:- £199.00 per pair MXF900 WIS" D14f" H5rr" (3U) ibl FC12-100 WATTS Freq Range 45Hz.20KHz, Sens 100dB, Size H546 W380 D300mm PRICE;- £179.00 per pair PRICES:- MXF200 £175.00 MXF400 £233.85 ibl WM12 200 WATTS Freq Range 40Hz-20KHz. Sens 97dB, Size H418 W600 D385mm MXF600 £329.00 MXF900 £449.15 PRICE:- £125.00 EACH SPECIALIST CARRIER DEL. £12.50 EACH SPECIALIST CARRIER DEL:- £12.50 per pair, Wedge Monitor £7.00 each Optional Metal Stands PRICE:- £49.00 per pair Delivery:- £6.00 OMR X03-S STEREO 3-WAY ACTIVE CROSS 0VERI SWITCHABLE 2-WAY ibl IN-CAR AUDIO BASS BOX tO/tOO^^H INCREDIBLE VALUE The new ibl In-Car Audio Bass Box has been designed with a sloping front to reduce internal standing waves. The bass box incorporates a 10 inch 4 ohm loudspeaker with a genuine ') o o o o 100 watts R.M.S. output resulting in powerful and accurate bass reproduction. / BASS/MID X TOP\^ FEATURES:- * Cabinet manufactured from MDF and 'BASSX,MID/^J0P / s /^ASSX, MID/TOP \ sprayed in a durable black shiny HAMMERITE finish. * CONFIGURED 3 WAY 2 WAY BASS/MID COMBINED 2 WAY MID/TOP COMBINED Fitted with a 10 inch loudspeaker with rolled rubber FEATURES: Advanced 3 Way Stereo Active Cross-Over (sirtchable two way), housed in a 19' x 1U case. Each channel edge and coated cone assembly * The top of the has three level controls: Bass, Mid & Top. The removable front fascia allows access to the programmable OIL cabinet incorporates gold plated connection switches to adjust the cross-over frequency; Bass-Mid 125/250/500Hz, Mid-Top 1.8/3/5Hz, all at 24dB per terminals. SPECIFICATION:- lOOWatts R M S. 200 octave. The 2/3 way selector switches are also accessed by removing the front fascia. Each stereo channel Watts Peak (Music).Ported reflex.critically tuned. can be configured separately. Bass Invert Switches are incorporated on each channel. Nominal 775mV Size;- H405 W455 D305mm. input/output. Fully compatibio with OMR Rack Amplifier and Modules. PRICE:- £79.00 + E6.00P&P PRICE;- £117.44 + £5.00 P&P SUPPLIED READY OMR MOS-FET POWER AMPLIFIER MODULES BUILT AND TESTED VARIABLE SPEED These modules now enjoy a world wide reputation for quality, reliability and performance at a realistic price Four SOUNDLAB CDJ1700 CD PLAYER models are available to suit the needs of the professional and hobby market i e Industry, Leisure. Instrumental and Hi-Fi etc When comparing prices. NOTE that all models include toroidal power supply, integralheat sink, glass fibre P C B and drive circuits to power a compatible Vu meter All models are open and short circuit proof THOUSANDS OF MODULES PURCHASED BY PROFESSIONAL USERS OMP/MF 100 Mos-Fet Output power 110 watts R.M.S. into 4 ohms, frequency response 1Hz 100KHz 3dB. Damping Factor >300, Slew Rate 45V/US, T.H.D typical 0.002%, Input Sensitivity SOOmV, S.N.R. 110dB Size 300 x 123 x 60mm. PRICE:- £42.85 + £4.00 P&P The new CDJ1700 now offers a tough build quality boasting an all new shockproof OMP/MF 200 Mos-Fet Output power 200 watts transport mechanism, frame accurate cueing and wide range pitch control. The R.M.S. into 4 ohms, frequency response 1Hz - 100KHz CDJ1700 looks after the CD's while the operator looks after the sound. 3dB. Damping Factor >300, Slew Rate 50V/uS. T.H.D. FEATURES: typical 0.001%, Input Sensitivity SOOmV, S.N.R. -110dB. *19"X2U RACK MOUNTING *FULLY VARIABLE PITCH CONTROL PLUS/MINUS 16% *PITCH BLEND *3 BEAM LASER PICKUP *1 BIT 8 X OVERSAMPLING DAC *CUE AND LOOP FACILITY * TRACK SKIP Size 300 x 155 x 100mm. WITH FF/REV * DIGITAL AND ANALOGUE OUTPUTS *CONTINUOUS/SINGLE TRACK PLAY *CLEAR PRICE:- £66.35 + £4.00 P&P BACKLIT MULTIFUNCTION DISPLAY *10 TRACK PROGRAM PLAY * TRACK ELAPSED, TRACK REMAINING AND DISC REMAINING TIME DISPLAYS OMP/MF 300 Mos-Fet Output power 300 watts SPECIFICATION:- Freq response. 20Hz-20KH2 S/N ratio >80dB THD <0 09%(1KHz) Channel R.M.S. into 4 ohms, frequency response 1Hz 100KHz separation...>80dB(1KHz) Max output voltage...2Vrms Power 220 240Vac 50 60Hz Size W 482 H 88 3dB. Damping Factor >300, Slew Rate 60V/uS. T.H.D. D 250mm Weight 4 18Kg PRICE:-£225.00 + £5.00 PAP typical 0.001%, Input Sensitivity 500mV, S.N.R 110dB Size 330 x 175 x 100mm. STEREO DISCO MIXER MPX-7700 ECHO & SOUND EFFECTS PRICE:- £83.75 + £5.00 P&P * 4 STEREO INPUT CHANNELS OMP/MF 450 Mos-Fet Output power 450 watts * 2 DJ MIC INPUT R.M.S. into 4 ohms, frequency response 1Hz 100KHz CHANNELS 3dB, Damping Factor >300, Slew Rate 75V/uS. * 2X7 BAND GRAPHIC T.H.D. typical 0.001%, Input Sensitivity 500mV, S.N.R. EQUALISERS 110dB, Fan Cooled. D C. Loudspeaker Protection. 2 * HEADPHONE Second Anti-Thump Delay. Size 385 x 210 x 105mm. MONITOR WITH PFL PRICE:- £135.85 +£6.00 PAP a ASSIGNABLE OMP/MF 1000 Mos-Fet Output power 1000 watts CROSSFADE R.M.S. into 2 ohms. 725 watts R.M.S. into 4 ohms, * DIGITAL ECHO frequency response 1Hz lOOKHz 3dB, Damping STEREO DISCO MIXER WITH;- *2X7 GRAPHIC EQUALISERS *2 MONO MIC INPUTS *DJ MIC Factor >300, Slew Rate 75V/uS, T.H.D. typical WITH FADER. TALKOVER AND VOICE CHANGER *4 STEREO CHANNELS WITH INDIVIDUAL 0.002%, Input Sensitivity 500mV. S.N.R. HOdB, Fan FADERS AND ASSIGNABLE CROSSFADE *CHANNELS SWITCHABLE, TURNTABLE (MAG CARTRIDGE). CD. LINE. TAPE. ETC. *ECHO WITH BALANCE. REPEAT AND DELAY Cooled. DC. Loudspeaker Protection. 2 Second ♦ HEADPHONE MONITOR WITH PREFADE LISTEN *CHOICE OF 6 SOUND EFFECTS *STEREO Anti-Thump Delay. Size 422 x 300 x 125mm. MONO SWITCH *2 X LED VU METERS *MASTER FADER *OUTPUT 775mV PRICE:- £261.00 + £12.00 P&P ♦ SIZE:-482X240X115mm *POWER:-230V Ap50/60Hz PRICE:- £169.00 + £5.00 P&P NOTE: MOS FET MODULES ARE AVAILABLE IN TWO VERSIONS: STANDARD INPUT SENS SOOmV, BAND WIDTH lOOKHz. OR ★ IDEAL FOR USE IN DISCO'S / RAVES. PEC (PROFESSIONAL EQUIPMENT COMPATIBLE) INPUT SENS SOUNDLAB MINI STROBE * EDUCATIONAL EXPERIMENTS ETC. 775mV. BAND WIDTH SOKHz ORDER STANDARD OR PEC A top quality mini strobe with high light intensity for its size and variable flash rate adjustment. Housed in a silver/black steel case with adjustable mounting bracket. * Flash Rate:- Adjustable from zero to ten flashes per B.K. ELECTRONICS second * Mains Powered complete with plugged lead * 230V AC 50/60Hz * Size:-125 X 84 X 52mm PRICE:- £19.99 + £2.20 P&P UNIT 1 COMET WAY, SOUTHEND-ON-SEA. ESSEX, SS2 6TR. @ AMOUNTDELIVERY £30.00.CHARGES; OFFICIAL PLEASE ORDERS INCLUDE FROM AS ABOVE.TO SCHOOL.COLLEGES. A MAXIMUM TEL.: 01702 527572 FAX.; 01702-420243 V GOVT. BODIES.PLCs ETC. PRICES INCLUSIVE OF VAT SALES COUNTER-CREDIT CARD ODERS ACCEPTED BY POST PHONE OR FAX Web:- http://www.bkelec.com E-mail:- Salesebkelec.comz 1 r Order your catalogue now I S3 J on 0±702 554000 ELECTRONICS or visit and collect from one of our 48 stores nationwide. You can also purchase your catalogue from your local Maplin store, WH Smith and John Menzies. CATAL THE NEW CATALOGUE UBLE CD OUT NOW 53* • FREE 30 d • Order code C £3.99 electronii &bevor 9S-{ Companion CO £1.95 electronics^ &bewnd 1 to better selection and service Telephone 01702 554000 with your enquiry The catalogue costs just £3.99 plus p-t-p* and the CD Rom is available at just £1.95 plus p-t-p* including free datasheet CD Rom. "(Add 50p for P&P). Orders outside the UK please send £8.99 or 21 IRCs for Airmail in Europe or surface mail outside Europe. Send £16.04 or 37 IRCs for Airmail outside Europe to: Maplin Electronics. PO Box 777. Rayleigh. Essex. England. SS6 8LU. Prices include VAT and are subject to change. All items subject to availability. E+OE WHEN ORDERING PLEASE QUOTE PRIORITY CODE MA095