In this video from Youtuber LOOK MUM NO COMPUTER, quite a synth mastermind we must say, shows us how he uses a Gameboy to act as a MIDI controller to communicate with his modular synthesizers and drum machines.

What allows his Gameboy rig to work is both an Arduino and LSDJ (Little Sound Dj). The Arduino uses an open-source code repository called Arduinoboy to allow MIDI messages to be transferred to and from the Gameboy, and LSDJ is what mechanizes the Gameboy to work with the MIDI messages similar to a DAW.

He also made DIY drum pads using tin-foil.