It speaks MIDI, but not with a musically useful layout.
Acting as a MIDI translator lets us create a isometric keyboard layout, and add features we can think of, such as a step sequencer.
Pictured is an Arduino with a USB 2.0 Host shield.
And because USB-MIDI is part of the protocol, the USB part of the code is not particularly scary.
The code is duct tape between:
- Arduino MIDI library so that it can easily output MIDI on hardware serial, so you can wire in a 5-pin DIN port
- in my code also the USB MIDI library though this seems to have been merged into the host shield code in current versions.