[Jarek Lupinski] wanted an instrument that would let him play chiptunes live, without a need for pre-programming a cartridge for playback during a concert. His preferred hardware is an original Nintendo Entertainment System because of its familiar nostalgic sound. After picking up a lot of 5 broken NES units he set out to build a midi-compliant device.
The five NES units he bought had nothing wrong with them other than the 70-pin cartridge connector. He fixed them all, then de-populated the board on one and tried to build out a circuit on a breadboard. After much trial and error, forum searching, and conversations with others who were familiar with the hardware he got the circuit working. He’s posted a schematic and had a board fabricated which takes the transplanted chips and transforms them into an instrument. Check out the test notes being played by an Arduino Mega after the break.