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Trinkey MIDI Theramin (will also work on any other CircuitPyton devices with `touchio`)
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# Trinkey Theramin! | |
# 2021 @todbot | |
# | |
import time | |
import board | |
import neopixel | |
import touchio | |
import usb_midi | |
import adafruit_midi | |
from adafruit_midi.note_on import NoteOn | |
from adafruit_midi.control_change import ControlChange | |
midi = adafruit_midi.MIDI(midi_out=usb_midi.ports[1], out_channel=0) | |
leds = neopixel.NeoPixel(board.NEOPIXEL, 4, brightness=0.2, auto_write=True) | |
# announce we're alive and wait for things to stabilize | |
# before creating touch pins so their raw_value baseline are okay | |
leds.fill(0xff00ff) | |
time.sleep(1.0) | |
leds.fill(0) | |
touch1_pin = touchio.TouchIn(board.TOUCH1) | |
touch2_pin = touchio.TouchIn(board.TOUCH2) | |
# a litlte helper class for noise filtering | |
class RunningAverage: | |
def __init__(self,count): | |
self.count = count | |
self.i = 0 | |
self.buf = [0] * self.count | |
def add_value(self,val): | |
self.buf[self.i] = val | |
self.i = (self.i + 1) % self.count | |
def average(self): | |
return sum(self.buf)/self.count | |
base1 = int(touch1_pin.raw_value * 1.02) | |
base2 = int(touch2_pin.raw_value * 1.02) | |
avg1 = RunningAverage(8) | |
avg2 = RunningAverage(8) | |
note_on = False | |
note = 60 # C4 in MIDI land | |
velocity = 64 # half | |
while True: | |
avg1.add_value( touch1_pin.raw_value ) | |
avg2.add_value( touch2_pin.raw_value ) | |
r = 0 | |
g = min(max(avg1.average()-base1, 0),255) | |
b = min(max(avg2.average()-base2, 0),255) | |
leds.fill( (r,g,b) ) | |
if g > 10: # hand present | |
if not note_on: | |
midi.send(NoteOn(note, velocity)) | |
print(time.monotonic(),"******* ON!") | |
note_on = True | |
else: | |
if note_on: | |
midi.send(NoteOn(note, 0)) # release | |
print("------ OFF!") | |
note_on = False | |
if g > 10: # hand present | |
midi.send(ControlChange(10, 64+int(g//4))) # 10 = filter cutoff | |
if b > 10: # hand present | |
midi.send(ControlChange(7, 64+int(b//4))) # 7 = filter resonance | |
time.sleep(0.001) | |
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