MIDI input example for the Pimoroni Tiny 2040 board

code.py

# This example lights the RGB LED on Tiny 2040 to a different colour 
# for each note in the octave. Listens on all MIDI channels by default.

import board
import adafruit_rgbled

import usb_midi
import adafruit_midi

from adafruit_midi.note_on import NoteOn
from adafruit_midi.note_off import NoteOff

# Red, green, and blue LED pins
RED_LED = board.LED_R
GREEN_LED = board.LED_G
BLUE_LED = board.LED_B


def hsv_to_rgb(h, s, v):
    # Convert an HSV (0.0-1.0) colour to RGB (0-255)
    if s == 0.0:
        rgb = [v, v, v]
    
    i = int(h * 6.0)

    f = (h*6.)-i; p,q,t = v*(1.-s), v*(1.-s*f), v*(1.-s*(1.-f)); i%=6
    
    if i == 0:
        rgb = [v, t, p]
    if i == 1:
        rgb = [q, v, p]
    if i == 2:
        rgb = [p, v, t]
    if i == 3:
        rgb = [p, q, v]
    if i == 4:
        rgb = [t, p, v]
    if i == 5:
        rgb = [v, p, q]

    rgb = tuple(int(c * 255) for c in rgb)

    return rgb


# Set LED up as common anode LED
led = adafruit_rgbled.RGBLED(RED_LED, BLUE_LED, GREEN_LED, invert_pwm=True)
led.color = (0, 0, 0)

# Set up USB MIDI to listen on all channels
midi = adafruit_midi.MIDI(midi_in=usb_midi.ports[0])

while True:
    # Receive MIDI message
    msg = midi.receive()

    if isinstance(msg, NoteOn):
        # If it's a note on message, turn the LED on

        # Calculate a hue that maps the 12 notes in an octave to values from 0.0 to 1.0
        h = msg.note % 12 / 12
        s = 1.0
        v = 1.0

        r, g, b =hsv_to_rgb(h, s, v)

        # Set LED colour
        led.color = (r, g, b)

    elif isinstance(msg, NoteOff):
        # If it's a note off message, then turn the LED off
        led.color = (0, 0, 0)