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Copyright Ó 2004, Wimborne Publishing Ltd (408 Wimborne Road East, Ferndown, Dorset, BH22 9ND, UK) and TechBites Interactive Inc., (PO Box 857, Madison, Alabama 35758, USA) All rights reserved. WARNING! The materials and works contained within EPE Online — which are made available by Wimborne Publishing Ltd and TechBites Interactive Inc — are copyrighted. You are permitted to make a backup copy of the downloaded file and one (1) hard copy of such materials and works for your personal use. International copyright laws, however, prohibit any further copying or reproduction of such materials and works, or any republication of any kind. TechBites Interactive Inc and Wimborne Publishing Ltd have used their best efforts in preparing these materials and works. However, TechBites Interactive Inc and Wimborne Publishing Ltd make no warranties of any kind, expressed or implied, with regard to the documentation or data contained herein, and specifically disclaim, without limitation, any implied warranties of merchantability and fitness for a particular purpose. Because of possible variances in the quality and condition of materials and workmanship used by readers, EPE Online, its publishers and agents disclaim any responsibility for the safe and proper functioning of reader-constructed projects based on or from information published in these materials and works. In no event shall TechBites Interactive Inc or Wimborne Publishing Ltd be responsible or liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or any other damages in connection with or arising out of furnishing, performance, or use of these materials and works. ISSN 0262 3617 PROJECTS . THEORY . NEWS . COMMENTS . POPULAR FEATURES . VOL. 33. No. 8 AUGUST 2004 Cover illustration by jgr22 www.epemag.wimborne.co.uk EPE Online: www.epemag.com Projects and Circuits EPE SCORER by David Coward 528 Score with the technological solution for quizmasters and sportsmasters! KEYRING L.E.D. TORCH by John Ellis 540 An “easy-build” torch that will give many hours of pleasure EPE PIC MAGNETOMETRY LOGGER – 2 by John Becker 543 Logging your search for magnetic fields that might reveal hidden artifacts SIMPLE F.M. RADIO by Raymond Haigh 550 An out-of-the-rut domestic receiver INGENUITY UNLIMITED – Sharing your ideas with others 562 Let There Be Light; Manual Bit-Stream Selector; Visual Illusion Series and Features CIRCUIT SURGERY by Alan Winstanley and Ian Bell 538 In the L.E.D. Driving Seat – answering basic l.e.d. questions TECHNO TALK by Andy Emmerson 548 The art of disguise now plays its role in the comms arena NET WORK – THE INTERNET PAGE surfed by Alan Winstanley 559 Comments on PC upgrading and software selection TEACH-IN 2004 – 10. Motor Control by Max Horsey 564 Concluding our 10-part tutorial and practical series – in which we have been showing how to apply electronics meaningfully PIC N’ MIX by Andrew Jarvis 579 “Hello” again – simulators, timers and finishing touches PIC TO PS/2 MOUSE AND KEYBOARD INTERFACING by John Becker 581 How to use a PS/2 keyboard or PS/2 mouse with your PIC designs INTERFACE by Robert Penfold 588 More about accessing a PC’s parallel port via INPOUT32.DLL Regulars and Services PIC PROJECTS VOL 1 CD-ROM Invaluable to all PICkers! 522 A plethora of 20 “hand-PICked” EPE past projects BACK ISSUE CD-ROMS Single-source shopping for issues you’ve missed 523 EDITORIAL 527 NEWS – Barry Fox highlights technology’s leading edge 535 Plus everyday news from the world of electronics READOUT John Becker addresses general points arising 574 CD-ROMS FOR ELECTRONICS 576 A wide range of CD-ROMs for hobbyists, students and engineers SHOPTALK with David Barrington 587 The essential guide to component buying for EPE projects DIRECT BOOK SERVICE 590 A wide range of technical books available by mail order, plus more CD-ROMs © Wimborne Publishing Ltd 2004. Copyright in all drawings, photographs and articles published in PRINTED CIRCUIT BOARD AND SOFTWARE SERVICE 593 EVERYDAY PRACTICAL ELECTRONICS is fully PCBs for EPE projects. Plus EPE project software protected, and reproduction or imitations in whole or ADVERTISERS INDEX 596 in part are expressly forbidden. Our September 2004 issue will be published on A Thursday, 12 August 2004. See page 519 for details Readers Services Editorial and Advertisement Departments 527 Everyday Practical Electronics, August 2004 517 NEXT MONTH RADIO CONTROL FAILSAFE This failsafe unit was developed for use in radio control (RC) models, originally for combat robots, but it can be applied to any land-based RC model. There is a statutory requirement for such a failsafe device, in particular with the rules associated with the use of fighting robots. The safety aspect is, of course, of paramount importance. In RC systems, especially when there is a fault, such as in the case of the loss of transmitter signal at the receiver, the effect could be to send the robot or model into uncontrollable action and cause damage to property, the model itself, or indeed to bystanders. This unit is designed to sense the moment of failure of the RC system and put the robot or model into a safe condition, rendering it motionless. It is “transparent” during normal operation, but during a fail situation it provides the servo or speed controller with a reliable and steady train of pulses. When the unit is used with a speed controller, on a model boat for instance, the latter’s supply can be switched off via a relay during failsafe, and the controller put into neutral – a belt and braces approach maybe, but it is better to err on the side of caution! ALPHAMOUSE GAME Do you remember those childhood toys which comprised a square frame enclosing 15 or more letters that you slid around to arrange into different orders? Perhaps even your children have one now. In their day they were the forerunners of Rubic’s Cube, before both became ousted by PlayStation and the like. NEW SERIES Recently, the author was considering how best to illustrate in a simple fashion the way in which a PC’s mouse could be put to alternative good LIGHT EMITTING use, following on from his article PIC to PS/2 Mouse and Keyboard Interfacing (Aug ‘04). Somehow, these letter frames came to mind, and DIODES sparked off a series of high-speed bashings at the keyboard to write the Operation and Applications code for a modern equivalent. The result of just a few hours coding and programming is this AlphaMouse This short series of articles examines Game, in which a 2-line 16-characters (per line) alphanumeric liquid crystal the features, construction and display replaces the lettered frame, and a PC’s PS/2 mouse controls the behaviour of l.e.d.s. It looks at the movements of 31 letters around the 32-position area. electrical characteristics of different l.e.d. types and examines various ways of biasing them. In particular, it WART ZAPPER contrasts the merits of different l.e.d. driver circuits, and examines some of As improbable as it may seem, the common wart may be destroyed with a the many special-purpose l.e.d. driver simple circuit that uses a tiny keyfob battery delivering a boosted 24V to the i.c.s that are currently available. The skin. Taking into account the resistance of the skin, this translates to just 100mA or so passing through the wart internally. series concludes by looking at some Four successive prototypes were tested on several volunteers, as well as of the more unusual applications for two prototypes being tested by doctors. The final prototype achieved close l.e.d.s, and discovering how light to a 100% success rate with the common wart (a brown or skin-coloured, emitting diodes have not just one, but rough wart), and 100% success with plain warts (a very flat wart). four different uses. The Wart Zapper’s high success rate does not, of course, guarantee that it Two allied constructional projects will will work in very case, but it is certainly worth a try. A simple, inexpensive also be described: a Volt Checker and project using around a dozen components. a Logic Probe. NO ONE DOES IT BETTER DON'T MISS AN ISSUE – PLACE YOUR ORDER NOW! Demand is bound to be high SEPTEMBER 2004 ISSUE ON SALE THURSDAY, AUGUST 12 Everyday Practical Electronics, August 2004 519 Quasar Electronics Limited Add £2.95 P&P to all UK orders or 1st Class Recorded – £4.95. PO Box 6935, Bishops Stortford, Next day (insured £250) – £7.95. Europe – £5.95. Rest of World – £9.95 (order online for reduced price UK Postage). CM23 4WP We accept all major credit/debit cards. Make cheques/POs Tel: 0870 246 1826 payable to Quasar Electronics Limited. Fax: 0870 460 1045 Prices include 17.5% VAT. MAIL ORDER ONLY. Call now for our FREE CATALOGUE with details of over 300 E-mail: [email protected] high quality kits, projects, modules and publications. CREDIT CARD 00 88 77 11 SALES 717717 71687168 Helping you make the right connections! ABC Maxi AVR Development Board NEW! DTMF Telephone Relay Switcher PIC & ATMEL Programmers The ABC Maxi board Call your phone number has an open architec- using a DTMF phone from We have a wide range of low cost PIC and ture design based on anywhere in the world ATMEL Programmers. Complete range and Atmel’s AVR and remotely turn on/off documentation available from our web site. AT90S8535 RISC any of the 4 relays as Programmer Accessories: microcontroller and is desired. User settable 40-pin Wide ZIF socket (ZIF40W) £15.00 ideal for developing new designs.