The project is a four channel, microprocessor-controlled light dimmer. It could be used in theatrical and other applications. It accepts input from a wide range of interfaces: RS232 input, DMX512 (theatrical lighting standard) or RS485, or a Musical Instrument Digital Interface (MIDI). It uses phase-angle firing of triacs to control the power delivered to the lamp loads. The firmware in the microcontroller handles all functions, from decoding the protocol on either of the input interfaces through to timing the firing of power triacs for the output.

Here are some pictures of the completed project:

Finished project
With the cover off
The dimmer's PCB

In the pictures there's a coaxial DC power jack on the end of a pair of purple wires. I was supposed to have a PCB mounted power transformer, but my source never provided one, so I used a 12V AC plug-in transformer to power the circuit.

Also in the pictures you can see that two of the triac's leads are crossed over each other. This was due to a pin assignment issue in the PCB layout; the full details are in the final report.

Please see the documentation link in the menu to the left for the full details of the project, including the source.

I also wrote a WinAmp visualization plugin to control the dimmer. It uses WinAmp's beat-detection and frequency analysis capability to control the connected lights in various ways (strobe, chaser, "colour organ"). The code seems to have been lost since I left school, but it wasn't very difficult to produce. I started with an example AVS plugin provided by Nullsoft, and added code to write intensity values to the serial port.