October 2010

Railpower IV (Part 1) Model train/ railroad controller

Our best ever model train controller! This ultra high performance unit features an infra red control and we believe it’s the finest train controller project that’s ever been published! Features include:

• 16-17V output up to 6 amps
• PIC 16F88 micro based, H-bridge power control
• Pulse power for extra smooth low-speed operation
• Back-EMF detection for speed regulation
• IR remote control
• Front panel speed control
• LCD bargraph of speed display
• Adjustable simulated inertia with on-off
• Adjustable braking (stop) inertia
• Forward / reverse lockout
• Overload protection

In Part 1 this month the circuit operation is outlined and in Part 2 next month full constructional details are provided, along with all necessary colour diagrams and photographs to enable you to build this exciting project with confidence.

LED Strobe & Tachometer (Part 1)

This versatile piece of equipment lets you observe and measure the RPM of rotating machinery using a stroboscopic effect. It provides three different measurement methods on its 2-line 16 character LCD which indicates RPM and frequency. It caters for generated or triggered strobe, slotted or reflective triggering, and has an adjustable flash period and more. Includes a 1W Luxeon-type white LED. PIC 16F88 based, hex code available from our Library.

In Part 1 most of the assembly details are provided, including the circuit board and LED-based strobe unit. Part 2 shows how to build the IR reflector amplifier and photo-interrupter boards, and operating instructions are given.

Replacement CDI Module for small petrol engines

If the capacitor discharge ignition (CDI)  on your motorbike, outboard or similar small petrol engine is failing then our replacement module could be an ideal repair, and at a much lower cost than proprietary ones. Our article describes how CDI works followed by constructional details and testing of the straightforward circuit.

Bridge Adaptor for stereo power amplifiers

Would you like to connect a stereo amplifier in ‘bridge mode’ in order to deliver double the power to a speaker system? This bridge module adaptor allows exactly that, without any modifications being needed to the power amplifiers themselves. It uses dual op-amps to provide signals in-phase and out-of-phase.

Also in this month’s EPE:

• Recycle-It! Our superior salvaging specialist describes the plunder and booty that’s available inside old personal computers, an Aladdin’s cave of goodies!
• Circuit Surgery continues its comprehensive analysis of Total Harmonic Distortion (THD).
• PIC n’ MIX continues with the evolution of a Propeller-based Internet computer.
• Interface – for PC users – continues with more serial interface topics.
• Ingenuity Unlimited – more readers’ circuit ideas
• Techno-Talk – tech news