A cheap and simple UV exposure box for creating PCB's using the photoresist method. The current solution is huge and inconvenient.
The box will consist of a frame, a matrix of UV LEDs and a timer circuit. The solution will be geared towards 10x16cm copper clad boards, and will therefore have a small form factor. For the timer circuit I propose using one of my ATMEGA88's and an LCD module. The box will be powered by 12V and by putting LEDs in series (every 2 or 3 LEDs, depending on Vacross) I hope to keep wattage down.
500 UV LEDs are currently on a boat from China towards the space. This should be enough for at least 1 decent size box and a tanning bed.
Update June 2013: Almost finished soldering the boards. Each 10x16 prototype board contains 12 x 18 = 216 LEDs, and the enclosure will house 2 boards with 432 LEDs in total in a 20 x 16 configuration. For each 3 LEDs (in series) there is a single 68Ohm resistor. Total amperage per board is around 1.4A (observed).