August 2012

Ultrasonic Cleaner

This is the ultimate ‘bubble bath’ for hard-to-clean or intricately-shaped parts. Unlike small consumer versions this one is designed for larger mechanical parts, ornate bric-a-brac, fabrics that cannot be machine-washed, and more besides.  The rugged design uses e.g. a 2 gallon water cistern as a tank and the PIC-powered circuit generates a high voltage signal to drive an ultrasonic transducer that instigates the cleaning action.

 
A sweep-frequency feature produces varied-sized bubbles to protect more delicate items, with higher-power sweep mode available. Built-in timer. Full details of theory and construction are included, with source code downloadable free from our Library.

Electrolytic Capacitor Reformer
& Tester (Part 1)

A useful item of test equipment for vintage valve radio or audio restorers, this PIC-micro based test gear can recondition many old electrolytic capacitors that have laid dormant over many years and developed high internal impedance as a result. It can work with standard voltages from 10V up to 630V and has a built-in timer and a number of features to ensure safety. The ideal way of resurrecting those vintage or hard-to-replace electrolytic capacitors.

High-Performance Microphone Pre-amplifier

If you’re struggling to get decent results using a microphone with your PC-based soundcard then this pre-amplifier could be for you! Many cheap mics. have a minimal output (say 10mV – 200mV) but audio ‘line level’ is about 775mV or higher:  audio equipment can actually handler 1V r.m.s. or more, so this microphone pre-amp project will improve the response and dynamics to help you get more from your audio system.

The tiny module provides a line level output from a cheaper unbalanced or balanced microphone and has very low noise and distortion. Provides unbalanced mono output, adjustable gain and offers a bias signal for electrets microphone capsules too.

High-power reversible DC Motor Speed Controller

Here’s an awesome 12V to 32V  30 Amp d.c. motor speed controller that’s easy to build. Available in either reversible or non-reversible versions, it has a high-power MOSFET output stage and features soft start, relay switching of motor direction and PWM speed control. Just the thing for electric buggies, 12V caravan movers, electric cycles or robotics.

Raspberry Pi – read all about it!

The new Raspberry Pi is an ultra low cost introduction to a programming environment. This feature reviews the new Raspberry Pi in depth and also hints at what’s in store for EPE readers! Get in at the beginning of the next great thing to arrive in hobby home computing – checkout the Raspberry Pi now.

Jump Start

Our series dedicated to newcomers to electronics offers a solar-powered charger suitable for many mobile devices.

Also in this month’s edition:

• PIC n MIX – completing the Uno32 Video Driver.
• Techno Talk – trends in weather forecasting and lightning storm observations.
• Circuit Surgery – Looking at National Semiconductor’s “Damn Fast” Buffers and associated topology.
• Interface – for PC users, an updated version of a 7-bit motor controller, now with full8-bit operation.
• Net Work – the Internet column –trends in behavioural advertising, and Google Play, their new entertainment portal.
• Max’s Cool Beans – ruminations on mechanical computing