He reckons it cost him about $5 to build each of his cheap USB MIDI adapters which receive notes and pedal data from the keyboard’s MIDI OUT and transmit ... his simple circuit on a bread ...

This allowed [JenShen] to scan the keyboard matrix with an Arduino and generate MIDI notes and send them to other synths. In the video after the break, you can check out [JenShen]’s circuit and ...