Ever wanted to plug your modern, USB-only MIDI keyboard into a synth that only has a classic DIN-5 or TRS 3.5mm MIDI input but you can't? Shouldn't there be a simple cable to convert USB to classic MIDI? It turns out, hosting a USB device is difficult, but you can build the USB MIDI Host Messenger to solve this key problem!

The USB MIDI Host Messenger solves the problem of how to connect USB MIDI keyboards and other controllers with classic synths and drum machines without inserting a whole dang computer in the middle. Plus, you can use it to filter MIDI messages in order to re-map MIDI channels, expand your Program Change choices, and spy on CC values.

The USB Host Feather RP2040 takes care of it all, running a single Arduino sketch. You can even build upon the code further to add more features such as CC re-mapping, note scale quantization, keyboard splitting, or even even build chord modes and arpeggiators.

Parts