| September 2001 | ||
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| Buy online from EPE - Back issues, project PCBs, books, CD ROMs are now all available direct from the UK, delivered worldwide. Payment accepted by Mastercard, VISA, Amex, Diners Club, Switch. Please note we do not sell components or kits for our projects. | ||
 LED Flashlights |
LED Flashlights - Two dazzling designs for LED torches, featuring a simpler hi-bri red LED version suitable for reading by, and a more sophisticated switched-mode circuit for an ultra-bright white LED version. Battery operated, efficient portable designs sure to impress your friends. |  Hi-tech LED Flashlight |
 Perpetual Loop Burglar Alarm |
Perpetual Projects Continuing with our mini circuits which use a modest solar panel to charge a "Gold Cap" capacitor during the day, which in turn powers a mini circuit "for ever"! This month a Loop Burglar Alarm, Touch Door Light (illuminates e.g. a keyhole at night for a short duration) and Perpetual Rain Alarm are described, based on the solar-power supply of the July issue. |  Perpetual Rain Alarm |
 Water Monitor |
 Water Monitor internals |
 Water Monitor LCD Display |
| Water Monitor - How much does it cost to keep your garden watered? To find out, build our Water Monitor, a PIC-controlled water flow measurement and auto shut-off device. You can also program in the cost of water per cubic metre and the Water Monitor will display the cumulative water consumption and cost on its LCD display. Requires PIC16F84 (source code available free from EPE's FTP site), plus an RS WaterFlow Sensor/ Solenoid Valve. 12V d.c. operated. | ||
60Hz Synchronous Clock Driver featuring a Jefferson Clock |
50 or 60 Hz Synchronous Clock Driver - due to popular demand, we present a dual frequency mains circuit which converts 230V a.c. 50 Hz British mains supply to a 115V a.c. 60Hz one suitable for powering imported synchronous clocks. Can also be modified for use overseas, to operate British 230V 50Hz equipment on a 115V 60Hz supply. |  Internal view of Synchronous Clock Driver. |
 Special feature — Controlling Flight — an insight into how electronics helps maintain air safety. |
 Circuit Surgery — Have you
ever wondered why capacitors are often placed in parallel across power
supplies? Is it to add their values together? Or why capacitors are
placed close by logic chips, microprocessors and more? The answer's in
this month's Circuit Surgery! |
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| Also in this issue, Ingenuity Unlimited (readers' own circuit ideas), New Technology Update trends in component package sizes. Circuit Surgery describes the use of decoupling capacitors in parallel. Net Work — The Internet Page — looks forward to satellite internet connections. All this and more in your favourite hobby electronics magazine! | ||
