Gt-Py Knob midi control

qtpy-knob-midi.py

# qtpy-knob-midi.py -- Mount a rotary encoder directly to an Adafruit QT Py,
#                        use it for midi CC message
#
# 2020 @todbot / Tod Kurt
# 2021 @David.Glaude / David Glaude

import time
import board
from digitalio import DigitalInOut, Direction, Pull
import rotaryio
import usb_midi
import adafruit_midi
from adafruit_midi.control_change import ControlChange

midi = adafruit_midi.MIDI(midi_out=usb_midi.ports[1], out_channel=0)

# button of rotary encoder
button = DigitalInOut(board.MOSI)
button.pull = Pull.UP

# Use pin A2 as a fake ground for the rotary encoder
fakegnd = DigitalInOut(board.A2)
fakegnd.direction = Direction.OUTPUT
fakegnd.value = False

encoder = rotaryio.IncrementalEncoder(board.A3, board.A1)

last_encoder_val = encoder.position

oldval = 63
newval = oldval

oldbut = button.value
newbut = oldbut

while True:
    diff = last_encoder_val - encoder.position # encoder clicks since last read
    last_encoder_val = encoder.position
    
    if diff != 0:
        newval=oldval+diff
        if newval > 127:
            newval = 127
        if newval < 0:
            newval = 0

    newbut = button.value
    if oldbut != newbut:                   # button pressed
        if newbut:
            button_midi = ControlChange(2, 0)
        else:
            button_midi = ControlChange(2, 127)
        midi.send(button_midi) #  sending CC message
####        print("button:", newbut)
        oldbut = newbut
    else:                                  # not pressed
        if oldval != newval:
            oldval = newval
            modWheel = ControlChange(1, newval)
            midi.send(modWheel) #  sending CC message
####            print("new:", newval)
    time.sleep(0.05)

Based on https://github.com/todbot/qtpy-knob
and on http://little-scale.blogspot.com/2016/07/simple-midi-rotary-encoder-with-teensy.html for possible midi CC value to use.

Alternate midi version by @todbot: https://github.com/todbot/qtpy-knob/blob/main/qtpy_knob_midi_cc.py