Communication to the computer is working now! Finally my diy monome arc is in a working state and the only features missing is a proper "stand by" mode, a sweet startup animation and the case.
In the next few days I will try to put together everythting I found out and make it available here for download. Schematics, firmare source code, suppliers, drawings of the case.
The "glass" rings and the light shapers are made of acrylic. They were laser cut by Ponoko.
Today (27.06.2013) I finished the last pcb and trimmed the firmware for a better performance. Now it's all there: the circuit, the pcbs, the firmware. Give me a few more days to make all of this available for you as a download.