Turn your Feather into a song-bird with this musically-enabled FeatherWing that adds MIDI input and output jacks to just about any Feather. You get both input and output DIN-5 MIDI jacks, a 3V optically isolator so you can interface with MIDI on 3.3V logic/power microcontrollers, and two blinky indicator LEDs underneath the jacks to help you know when data is sent and received.