Cool, was der Kerl gebastelt hat:
The Chipophone is a homemade 8-bit synthesizer, especially suited for live chiptune playing. It has been built inside an old electronic organ.
All the original tone-generating parts have been disconnected, and the keys, pedals, knobs and switches rerouted to a microcontroller which transforms them into MIDI signals. Those are then parsed by a second microcontroller, which acts as a synthesizer.
You can find more information about how the organ was modified on the making of page.
The synthesizer is implemented on an ATmega88, an 8-bit microcontroller with 1 kB of RAM and 8.5 kB of ROM. It receives MIDI data at a jumper-configurable baud rate and produces a 12-bit mono line out signal. What follows is a brief architectural overview.