Think your cool toy would make a great midi controller.. found a USB midi library for the 841 here:

https://github.com/mimuz/mimuz-avr-core/tree/master/arduino/libraries/HybridMidiAttiny

what do you think? possible? could it be made wireless by attaching your bluetooth board with a bit of hacking?

seems like all the pins are used in the schematic, not sure tho.

Thanks, Tefriot