Projects, articles and links to information that may interest Radio Amateurs and Electronics enthusiasts





The projects I have built basically fall into two categories; General Electronics and Amateur Radio.

Some of them are listed below.


General Electronics Projects

Power Fail / Emergency light controller :


This AVR processor driven controller monitors the 240v mains power and if it fails for a predetermined period, will switch on 12v lighting which can consist of fluorescent or more commonly, LED lights.

Several features can be programmed and three separately fused light circuits are used to provide maximum reliability in case of damage to one or more of the circuits. Battery monitoring can be selected to either switch off the lighting before the battery discharges into a damage causing state or allow the lights to remain on until insufficient battery power remains. ie an emergency situation. The controller has a security or fire alarm input which overides other operations and forces it into emergency mode which will provide lighting until the battery is flat.


Daytime Running Lights controller:


With vehicle safety being a primary consideration when purchasing a new car these day, Daytime Running Lights are a necessary item and already mandatory in some other countries with Australia following suit. With the Australian Design Rules being very explicit about the type, colour, location and operation of these lights, aftermarket controllers that can be easily installed in modern cars and conform to our ADRs are pretty well non-existent. So this controller takes the Australian Design Rules in consideration in its operation but has the option to work in European mode if desired.


Amateur Radio Projects

The Muter :


This module will allow muting of a radio output to prevent background audio interfering with another conversation and is connected between the radio and the extension speaker.

Several of these modules can be daisy chained thereby control on one, can mute or unmute all others meaning that multiple radios can be muted at the same time. Programmable timers allow for predetermined muting times. As well, a display of last audio received and current audio whilst in mute mode is obtained by lighting a multi coloured LED.


Pager Filter :


In Australia, the paging systems use frequencies just above the 2m band. This notch filter was built to reduce or elliminate the intermodulation distortion caused by these systems. The story tells of the models that were built before settling on a design with favourable results. Several amateurs around Melbourne are able to use 2m again.


Repeater Controller :


A project that was needed for a long time and took a long time to complete. Our Club's 6m Repeater badly needed an overhaul and so we took up the challenge. This is the story behind the project.


Rotator Controller:


Following the purchase of an antenna rotator minus its controller, I decided to build my own but with a twist - the ability to separately control two rotators. Of course it runs on an AVR processor.


Trimble GPS Monitor:


I purchased a Trimble Thunderbolt GPS based 10MHz disciplined oscillator and needed to have some form of permanent monitoring without connecting it to a PC. Putting everything into a cabinet and building this stand-alone display and controller module did the trick.