Australia $1.75 New Zealand $1.95 Malaysia $4.95 PRACTICAL SEPTE MBER 1985- £1-00 ELECTRON- MIC R OS - ELE CT R O NIC S- INTECS RF ACIN G Alarm Systems D.I.Y. Buyer's G de ndustrial Solderin Equipment-for the discerning amateur SEND FOR NEW CONCISE LEAFLETS ADCOLA 101 ELECTRONIC ACCESSORIES CONTROLLED include: SOLDERING SIDE CUTTERS STATION for precision soldering with accuracy suitable for use on MOS. FET etc 240V input - 24V on tool. Temperature range SNIPE NOSE PLIERS 120-420 C Many extra features `1(' SERIES SOLDERING TOOLS FOR ALL APPLICATIONS PLUS • Desoldering Braid K1000 micro soldering • Desoldering Guns K2000 general electronic • Tip cleaners soldering • Soldering aids K3000 heavy duty soldering • Lamps, Lenses etc 6 .2m .10.. ..S:/deri/7g • Small selection of tabs AD-IRON LONG LIFE 842LL 838L1. B5OLL (314 U 835LL B44LL 836LL 837LL 046LL B4OLL SOLDERING TIPS suitable for all Adcola soldering irons. For a no obligation demonstration, please contact: ADCOLA PRODUCTS LIMITED Gauden Road London SW4 6LH Telephone Sales (01) 622 0291 Telex 21851 Adcola G R O B OTIC S MI C R O S ELE CT R O NIC S INTE RF A CIN G ISSN 0032-6372 V OL U M E 21 N 9 9 S E P TE M B E R 198 5 C O NSTR UCTIO N AL PR OJECTS EXPERIMENTING WITH ROBOTS by Mike Abbott 10 Part One: Simple interface, plus a Latin-American dance? CAR BOOT ALAR M by D. Stone 22 Protect the contents of your car boot with this simple circuit RS232 TO CENTRONICS CONVERTER by Tom Gaskell BA (Hons) CEng MIEE 46 Serial to parallel interface suitable for many peripherals DIGITAL DELAY & SOUND SA MPLER WITH COMPUTER INTERFACE by John M. H. Becker 50 Part Four: Final part—interwiring diagram and software G E NE R AL FE AT U RE S ROBOTICS REVIE W by Nigel Clark 19 A regular look at robotics and cybernetics PLOTTER REVIE W by D. Whitfield MA MSc CEng MIEE 20 A "natural" pantographic drawing aid for the BBC-B Micro ALAR M SYSTE MS —DIY BUYER'S GUIDE by Brian Butler 25 An in-depth look at current trends and equipment/kits SPACE WATCH by Dr Patrick Moore OBE 34 BBC MICRO FORU M by D. Whitfield MA MSc CEng MIEE 36 Thermometer software SERPENT REVIE W by Dick Becker & Roger Gay 39 A close look at construction and control of SCARA's SEMICONDUCTOR CIRCUITS by Tom Gaskell BA(Hons) CEng MIEE 44 Baud Rate Generator (4702B) N E WS & C O M M E N T EDITORIAL 7 LEADING EDGE 16 READOUT 52 NE WS & MARKET INDUSTRY NOTEBOOK 18 P.C.B. SERVICE 53 PLACE 8 BAZAAR 35 This month's front cover picture shows a 21st Century working class robot checking the rac- ing results. His gears and hydraulics were supplied courtesy of Fischer Alarm Systems Technik. 0.I.Y. Buyer's de O UR OCT OBER ISS UE WILL BE O N SALE FRID AY, SEPTE MBER 6th, 1985 (see page 4) c I PC Magazines Limited 1985. Copyright in all drawings, photographs and articles published in PRACTICAL ELECTRONICS is fully protected, and reproduction or imitations in whole or part are expressly forbidden. All reasonable precautions are taken by PRACTICAL ELECTRONICS to ensure that the advice and data given to readers are reliable. We cannot, however, guarantee it, and we cannot accept legal responsibility for it. Prices quoted are those current as we go to press. Practical Electronics September 1985 BF1198 105 17P30C 37 2N914/5 32 2N5458/9 30 TRANSISTORS BFX29/84 35 T1P314 38 2N918 40 2N5485 36 WATFORD ELECTRONICS BFX84 35 TIP31C 45 2N930 20 2N5777 45 AC127/8 36 13C3085 16 T1P324 43 2N1131/2 • 40 2516027 32 250, HIGH ST., W ATFORD, HERTS VVD .1 2AN, ENGLAND BFX85/86 35 AC141/2 35 BC327/8 15 5FX87/88 28 TIP32C 45 2N1303/4/5 ' 2516109 60 Tel. Watford (0923) 40588. Telex: 8956095 VVAELEC AC176 35 BC337/8 15 BFY50/51 30 TIP334 70 2N1307 70 2N6290 70 AC187/8 35 8C441 34 8FY52 30 TI033C 75 2511613 30 2$4636 250 OR DERS NOR M ALLY DESP ATCHE D BY RETUR N OF POST AC188 35 BC461 34 BFY53 35 11P34A 85 2N167113 160 254671 250 AD142 120 BC477/8 40 BFY55 35 T1P34C 105 2N2160 325 254715 75 AD149 79 5C516/7 40 1IP354 120 2N22194/20A/ 2SC495/6 85 ALL DEVICES BRAND NEW. FULL SPEC. AND FULLY GUARANTEED. SEND CASH, P.O.'s OR CHEQUE BFY56 35 A0161/2 42 BC547/8 12 BEY64 40 1IP35C 130 21A/22A 25 2SC1061 250 WITH ORDER. GOVERN MENT AND EDUCATIONAL INSTITUTIONS OFFICIAL ORDERS ACCEPTED 95 BC549C 15 BFY90 80 TIP364 130 2512369A 18 85 (ACCESS ORDERS BY TELEPHONE 0923-50234). TRADE AND EXPORT INQUIRY WELCO ME. PS P AF118 AF139 40 8C556/7 15 25C1162 45 ADD £1 TO ALL CASH ORDERS. OVERSEAS POSTAGE AT COST. PRICES SUBJECT TO CHANGE. BRY39 50 11P36C 140 2N2646 45 AF239 55 BC558/9 15 88X20 30 TIP414 50 2N2846 80 25C1172/3 125 ..., Export orders no VAT. U.K. customers please add 15% VAT to total cost incl. p&p. We 8C107/8 12 BCY41142 30 55X29 45 1IP41B 52 2N29044/05A/ 25C1306 100 vA 1 stock thousands more items- It pops to visit on. Nearest underground/British Rail Station, BC107B 14 I3CY70 18 BSY26 35 TIP42A 55 0641074 26 25C1307 150 Watford High Street- Open Monday to Saturday, 9.00am to 6.00pm. Ample FREE Car parking. BC108B 14 BCY71 20 BSY95 35 TIP4213 58 2N2926G 10 25C1449 95 BC108C 14 BCY72 25 5U105 180 TIP120 70 2513053 26 25C1679 190 POLYESTER RADIAL LEAD CAPACITORS: 250V; 10n, 20n, 15n, 22n, 27n 6p; 33n, 47n, 68n, 100n 8p; 150n, 8C109 12 BCY78 30 BU205 190 1IP121 73 2N3054 55 25C1678 140 220n 10p; 330n, 470n 15p; 680n 19p; 1p 23p; 105 408; 202 4 58. BC10913 14 5D131/2 65 0U206 200 TIP141 120 2513055 50 25C1923 65 BC109C 14 B0133 60 BU208 200 T81142 120 2N3442 140 2SC1945 225 ELECTROLYTIC CAPACITORS (Values in pF). 500V: 10pF 52p; 4778p; 6.351: 047, 10, 1.5, 2-2,3-3, 8p; 4-7 25C1953BC114/5 90 30 B0135 45 MJ2955 90 T1P147 120 2N3615 199 9p; 10 10p; 15,22 12p; 33 15p; 47 12p; 68 16p; 10019p; 220 28p; 1000 70 8; 220099 p; 50 V: 6820 8; 100 BC117/8 25 1 40 Bit3 B_136/7 40 MJE340 54 TIP2955 70 2N3663 20 2SC1957 90 17p; 22024p; 40V: 6-8 15p; 22 9p; 3312p; 330, 470 32p; 1000 48 p; 220090 p; 25 V,4-7 .10,22,478 p; 100 5C140 38 MJE371 100 T1P3055 70 2N3702/3 10 25C1969 165 11p; 150 12p; 220 15p; 330 22p; 470 25p; 680, 1000 34p; 1500 42 p; 2200 50 p; 3300 76 p; 470092 p; 16V: BC142/3 38 BD140 40 m5.1 J E239055 997 0 T7, 1 I543s44 50 2N3704/5 10 2SC2028 85 2.5, 408p; 47, 68,300 9p; 125 12p; 220 13p; 330 16p; 470 20p; 68034p; 100027p; 1500 31p; 2200 36p; 4700 BC147/8 12 5D158 68 45 2N3706/7 10 25C2029 200 79p. BC147B 15 BD245 65 MPF102 40 TIS88A 50 2513708/9 10 28C2078 170 TAG-END TYPE: 64V: 4700 245p; 3300 145p; 2200 1209; POTENTIO METERS: Carbon Track, BC148C 10 5D434 70 MPF103/4 30 11590 30 2513710 10 25C2091 85 50V: 3300 155p; 2200 95p; 40V: 4700 160p; 2200 7 08; 3300 0,25W Log & Linear Values. 5C149 12 5D6954 150 MPF105 30 71591/93 32 2513771 179 25C2166 165 85p; 4000, 4700 75p; 10,000 250p; 15,000 27 08; 18V: 2200 8C149C 15 8D6964 150 MPS405 30 VK1010 99 2N3772 195 2SC2314 85 500W, 1K & 2K (LIN ONLY) Single 35p 200p; 25V: 4700 98p; 10,000 3209; 15,000 345p. 5C153/4 30 BF115 45 MPS406 25 VN1OKM 70 2513773 210 25C2335 200 5K0-2M0 single gang 350 BC157/8 14 BF154/8 30 MPS408 30 VN464F 96 2N3819 35 2SC2465 125 5K0-2M0 single gang D/P switch 95p TANTALU M BEAD CAPACITORS: BC159 11 BF167 35 MPSA12 32 VN66AF 110 2N3820 60 25C2547 40 51(0-2M0 dual gang stereo 99 P BC167A 14 I3F173 35 VN88AF 120 2N3822/3 60 25C2612 200 35V: 0.1p, 0,22, 0,33 15p 0-47, 0•68, 1-0,1 -5 16p 2,2, 3-3 18p 4,7, MPS455 30 5C168C 12 BF177 35 MP5456 30 VN89AF 120 2N3866 90 250234 75 6022 p 10 2 58 16V: 2-2, 13, 18p 4-7, 6,8, 10 18p 15 38p 22 SLIDER POTENTIO METERS 5C169C 12 BF178 35 MPSA70 40 ZTX107/8 12 2N3903/4 15 281(45 90 36p 33, 47 50p 100 95p 220 100p 1051: 15, 22 2 6p 33 , 47 0-25W log and linear values 60mm track 50p 10075p. 5C171/2 12 BF179 40 MPSUO2 58 ZTX109 12 2N3906/5 15 251(288 225 5K0-500K0 Single gang 8° P 5C173 15 BF194/5 12 MPSUO5 60 ZTX212 28 2N4037 80 2SJ83 225 5C177/8 16 BF198/9 18 SILVER MICA (pf) SIEMENS mulitlayer miniature MPSUO6 60 ZTX300 13 2N4058 15 2SJ85 225 PRESET POTENTIO METERS BF200 30 2, 3-3, 4-7, 6-8, 8-2, 10, 12, 18, capacitors. BC179/81 20 MPSU52 65 ZTX301/2 16 2N4061/2 15 3N128 115 0-1W 500-2-2M Mini Vert. & Hori7. 81/ 5C181 30 351I40 115 22, 27, 33, 39, 47, 50, 56, 68, 75, 250V: In F, 1n5, 2n2, 3n3, 4n 7, BF224 40 MPSU55 60 ZTX3O3 25 2N4264 30 0,25W 2200-4M7 Vert.