There are 2 examples of midi for Micro Python in this repository.

This is a simple midi example which uses the switch to trigger a sequence of notes.

in boot.py

import midi_switch

on your host run ttymidi (see below)

This contains a Controller class that implements a simple abstraction and serves as documentation of some of the standard midi protocol.

Add the following to main.py and import main in boot.py

import midi

serial = pyb.USB_VCP()


def midi_controller():
    """Use the accelerometer and the switch as a midi control."""
    instrument1 = midi.Controller(serial, channel=1)
    accel = pyb.Accel()
    switch = pyb.Switch()
    while 1:
        while not switch():
            pyb.delay(10)
        note = accel.x()
        velocity = accel.y()
        instrument1.note_on(note + 65, velocity + 65)
        while switch():
            pyb.delay(50)
        instrument1.note_off(note + 65)

In the console run the function

>>> midi_controller()

then disconnect the console and run ttymidi

$ ttymidi -s /dev/ttyACM0 -n MicroPythonMidi -b 9600 -v

The -v option will output the midi commands to the console.

To hear sound, connect the MicroPythonMidi output to your sound application input using a patchbay tool such as patchage, then press the button.

The orientation of the board will control the pitch and the volume of the note played.

ttymidi a tool to link a serial input to alsa as a midi I/O device.

It is available from https://github.com/cjbarnes18/ttymidi.git

Once compiled, to get it to communicate with Micro Python use the following options.

$ ttymidi -s /dev/ttyACM0 -n MicroPythonMidi -b 9600

Then use standard midi tools.

I generally use patchage to manage the connections, and Qsynth is a good synthesizer to get started with.