Melody Maker using Circuit Python

https://learn.adafruit.com/midi-melody-maker

MIDI CircuitPython

Build a custom MIDI instrument using CircuitPython! Use the MIDI FeatherWing and Feather M4 to power your musical projects using the classical 5-PIN DIN jacks. The 128x64 OLED with STEMMA QT makes it easy to add a screen with custom UI. Use potentiometers to change the modulation, key, beat division and modes to create an arrangement of MIDI notes.

Uses something called Feather M4 Express ATSAMD51 Cortex M4 - https://www.adafruit.com/product/3857