keybow2040/examples/midi-keys.py

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# SPDX-FileCopyrightText: 2021 Sandy Macdonald
#
# SPDX-License-Identifier: MIT
# Demonstrates how to send MIDI notes by attaching handler functions to key
# presses with decorators.
# You'll need to connect Keybow 2040 to a computer running a DAW like Ableton,
# or other software synth, or to a hardware synth that accepts USB MIDI.
# Drop the keybow2040.py file into your `lib` folder on your `CIRCUITPY` drive.
# NOTE! Requires the adafruit_midi CircuitPython library also!
import time
import board
from keybow2040 import Keybow2040
import usb_midi
import adafruit_midi
from adafruit_midi.note_off import NoteOff
from adafruit_midi.note_on import NoteOn
# Set up Keybow
i2c = board.I2C()
keybow = Keybow2040(i2c)
keys = keybow.keys
# Set USB MIDI up on channel 0.
midi = adafruit_midi.MIDI(midi_out=usb_midi.ports[1], out_channel=0)
# The colour to set the keys when pressed.
rgb = (0, 255, 50)
# Initial values for MIDI note and velocity.
start_note = 36
velocity = 127
# Loop through keys and attach decorators.
for key in keys:
# If pressed, send a MIDI note on command and light key.
@keybow.on_press(key)
def press_handler(key):
note = start_note + key.number
key.set_led(*rgb)
midi.send(NoteOn(note, velocity))
# If released, send a MIDI note off command and turn off LED.
@keybow.on_release(key)
def release_handler(key):
note = start_note + key.number
key.set_led(0, 0, 0)
midi.send(NoteOff(note, 0))
while True:
# Always remember to call keybow.update()!
keybow.update()