drum_track_sequencer.py

# SPDX-FileCopyrightText: 2024 John Park for Adafruit Industries
#
# SPDX-License-Identifier: MIT

"""
Drum Track Sequencer
 Feather RP2040, Motor FeatherWing, stepper motor,
 four reflection sensors (either MIDI out or synthio w amp)

"""
"""
# TO DO:
add rotary encoder for pause/play and bpm
"""
import time
import busio
from adafruit_seesaw import seesaw, rotaryio, digitalio
import asyncio
import board
from adafruit_motorkit import MotorKit
from adafruit_motor import stepper
import keypad
import usb_midi

i2c=busio.I2C(board.SCL, board.SDA, frequency=400_000)
seesaw = seesaw.Seesaw(i2c, addr=0x36)
seesaw.pin_mode(24, seesaw.INPUT_PULLUP)

encoder_button = digitalio.DigitalIO(seesaw, 24)
encoder_button_held = False
encoder = rotaryio.IncrementalEncoder(seesaw)
encoder_last_position = None

# Motor setup
kit = MotorKit(i2c=i2c)
motor_run=True

# Sensor setup
optical_pins = (board.D6, board.D9, board.D10, board.D12)
optical_sensors = keypad.Keys(optical_pins, value_when_pressed=False, pull=True)

# MIDI setup
midi = usb_midi.ports[1]
midi_notes = (36, 37, 38, 39)

def play_drum(note):
    midi_msg_on = bytearray([0x99, note, 120])  # 0x90 is noteon ch 1, 0x99 is noteon ch 10
    midi_msg_off = bytearray([0x89, note, 0])
    midi.write(midi_msg_on)
    midi.write(midi_msg_off)

async def check_encoder():
    while True:
        encoder_position = -encoder.position
        if encoder_position != encoder_last_position:
            encoder_last_position = encoder_position
            print(encoder_position)
        if not encoder_button.value and not encoder_button_held:
            encoder_button_held = encoder_button_held = True
            print("encoder button pressed")
        if encoder_button.value and encoder_button_held:
            encoder_button_held = False
            print("encoder button released")
        await asyncio.sleep(0)

async def check_sensors():
    while True:
        optical_sensor = optical_sensors.events.get()
        if optical_sensor:
            if optical_sensor.pressed:
                track_num = optical_sensor.key_number
                print("tripped", track_num)
                play_drum(midi_notes[track_num])
        await asyncio.sleep(0)

async def run_motor():
    while True:
        kit.stepper1.onestep(
                                direction=stepper.BACKWARD,
                                style=stepper.DOUBLE
        )
        await asyncio.sleep(0.002)  # motor speed


async def main():
    motor_task = asyncio.create_task(run_motor())
    sensor_task = asyncio.create_task(check_sensors())
    encoder_task = asyncio.create_task(check_encoder())
    await asyncio.gather(motor_task, sensor_task, encoder_task)

asyncio.run(main())