Here's what I wrote up on my LED head http://www.trippingthroughthedark.co...ment/led-head/

I started a rebuild, but progress has stalled. The idea of the rebuild is to separate the LED power circuits from the controller(s). The controller will simply send commands with I2C to an I2C compatible PWM chip, which will control the LED drivers. It's not necessary, but it the idea is to simplify things enough to make easy use of different controllers such as Raspberry Pi touchscreen or Arduino with keypad and basic display as I'm doing it now. It will also allow differing head configurations with a range of LED options. Using an inexpensive driver such as the Meanwell LDD series will give a lot of flexibility in LED wiring and power levels.