August 2009 Issue

A summary of this month's contents.

Rolling Code Keyless Entry System (Part 1)

This PICmicro-powered super-secure keyless entry system is perfect for many applications in auto, home or industry. It features a rolling code to assure higher levels of security. Our new design comprises a small IR keyfob-style transmitter and a separate receiver. Up to 16 separate transmitters can be synchronised.


Also features dual function with an independent output, two alarm inputs with adjustable exit and entry delays, two door strike outputs, arm/ disarm output and LED indicator, and 200-code look ahead feature. PIC16F628 based transmitter [surface mount devices ­- soldering skills preferable], free source code download and PCB/ pwb foils available from our Library.


Simple Data-logging Weather Station (Part 2)

This month’s follow-up article gets to the nitty-gritty of building the Weather Station. We include all practical blueprints and plans for constructing the tipping-bucket rain guage mechanism and a louvred Stephenson screen enclosure for the temperature sensor.


We also show how to download and display the weather data in a spreadsheet. It’s an immensely satisfying practical project that amateur meteorologists will enjoy building.


Fast Charger for NiMH Batteries

If you’re looking for a really versatile solution for charging a wide variety of NiMH cells (handles NiCds too), then EPE has the answer in the shape of powerful ‘intelligent’ PICmicro-controlled recharger! You can build it to suit any size cells or cell capacity and you can also set the charge rate.


Our Fast Charger has built-in protection features to safeguard your cells, including temperature detection (dT/dt) to prevent overheating. It can fast charge or trickle charge, and can charge from one to 15 cells simultaneously and battery packs up to 18V for both NiMH and NiCad types. A powerful and versatile unit, an essential bit of kit for every constructor’s workshop.


Recycle It!

Our increasingly popular feature on recycling surplus electronics bits and pieces shows you how to make a fantastic low-cost large display anemometer [wind speed detector] from a range of surplus  parts including a video head from an old VCR, the optics from an old PS/2 mouse  and an old car speedo or tacho (an old  VU meter will do though).


Breadboarding Projects Part 11 – Festive Lights

Rounding off our series specially written for beginners, a mini LED ‘Festive Lights’ circuit is described this month, will all breadboard layout information included as well, so that you can build the circuit with total confidence.


Also in this issue:


  • Ingenuity Unlimited – readers’ own circuits outlines an Optical Motion Detector, explaining how Ronchi grates come to the rescue of our reader’s quest for a solution.
  • Techno Talk – solar cells constructed from diatoms – single cell algae – could be the cost-effective answer to renewable energy.
  • Interface – more theory and principles for PC interfacing enthusiasts.
  • Circuit Surgery – our in-house ‘surgeon’ follow sup on filter theory, with filter design freeware highlighted this month.
  • PIC n’ MIX offers an RS232C terminal à la PIC!
  • Net Work – the Internet column – the lunatic antics of Nigerian spammers are saluted by our Internet-savvy columnist this month.


All this and lots more for every electronics enthusiasts in EPE Magazine every month.


Source code

PCB files


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