GitHub - abhishek29061992/msp430-midi-controller: A code example for MSP430 series microcontroller (MSP430G2553) that uses 32 (pressure insensitive) keys, an ultrasonic sensor (HC-SRO4) and a potentiometer (foot pedal in this case) to send signals
UMC32 USB-MIDI Controller
CHIP MIDI, circuito I/O MIDI completo per controller Midi Arduino/Teensy/ESP32 - Etsy Italia
DIY midi controller with 8 Velocity-Sensitive Drum Pads (on one chip Atmega328) 'Very simple' - YouTube