David DeGraw of Catskull Electronics has developed Teensyboy, an awesome little MIDI adapter for a Nintendo Gameboy.

This compact little shield is about the size of thumb drive and uses USB MIDI.  Simply plug it into into a computer and fire up your favorite digital audio workstation (DAW) and you’ll be jamming with your Gameboy before you know it.

There is also a Teensyboy Pro that includes a variety of modes to accommodate Little Sound DJ (LSDJ), Nanoloop and mGB.  It also has convenient mounting holes for installation into a case.

Vague Robots has some tutorial videos on using the Teensyboy Pro with LSDJ

The software is available on catskull’s gitHub repository.  It’s a fork of this Arduinoboy software by trash80.