first commit drum track sequencer

Drum_Track_Sequencer/code.py

@@ -0,0 +1,77 @@
+# SPDX-FileCopyrightText: 2024 John Park for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+"""
+Drum Track Sequencer
+ Feather RP2040, Motor FeatherWing, stepper motor,
+ four reflection sensors, USB MIDI out
+"""
+import asyncio
+import busio
+import board
+from adafruit_motorkit import MotorKit
+from adafruit_motor import stepper
+import keypad
+import usb_midi
+
+# Tempo setup
+BPM = 100  # user set value
+tempo_table = {  # motor speed seems non-linear, so we'll use a lookup table
+    110: 0.0004,
+    100: 0.001,
+    90: 0.002,
+    80: 0.003,
+    75: 0.004,
+    65: 0.005,
+    60: 0.006,
+    50: 0.008
+}
+def get_nearest_tempo(given_bpm):
+    nearest_table_item = min(tempo_table.keys(), key=lambda k: abs(k - given_bpm))
+    return tempo_table[nearest_table_item]
+motor_pause = get_nearest_tempo(BPM)
+
+i2c=busio.I2C(board.SCL, board.SDA, frequency=400_000)
+
+# 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)  # typical drum voice notes
+
+def play_drum(note):
+    midi_msg_on = bytearray([0x99, note, 120])  # 0x90 noteOn ch1, 0x99 noteOn ch10
+    midi_msg_off = bytearray([0x89, note, 0])
+    midi.write(midi_msg_on)
+    midi.write(midi_msg_off)
+
+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(0.008)  # don't check sensors constantly or motor speed reduced
+
+async def run_motor():
+    while True:
+        kit.stepper1.onestep(
+                                direction=stepper.BACKWARD,
+                                style=stepper.DOUBLE
+        )
+        await asyncio.sleep(motor_pause)  # motor speed-- smaller numbers are faster
+
+async def main():
+    motor_task = asyncio.create_task(run_motor())
+    sensor_task = asyncio.create_task(check_sensors())
+    await asyncio.gather(motor_task, sensor_task)
+
+asyncio.run(main())