Matseng designed DimBlue, an ATmega32u4 based USB controllable 16 channel light dimmer. Triacs which dim the lights are optoisolated from mains to provide protection from high voltages. The board is powered from mains voltage, via a PCB mounted transformer.
As an added bonus, the board has a footprint for a serial Bluetooth module, giving it the possibility of wireless control.
Via the forum.