Adding code for midi stomping pads

Adding code for MIDI stomping pads Learn Guide. Uses a CPX and four inputs. On input NeoPixels change color and MIDI note is sent

Circuit_Playground_Express_MIDI_Stomping_Pads/code.py

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+# SPDX-FileCopyrightText: 2021 Liz Clark for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+import board
+from digitalio import DigitalInOut, Direction, Pull
+import neopixel
+import usb_midi
+import adafruit_midi
+from adafruit_midi.note_on          import NoteOn
+from adafruit_midi.note_off         import NoteOff
+
+#  USB MIDI setup
+midi = adafruit_midi.MIDI(midi_out=usb_midi.ports[1], out_channel=0)
+
+#  NeoPixel setup
+pixels = neopixel.NeoPixel(board.NEOPIXEL, 10, brightness=0.02, auto_write=False)
+
+#  setup for digital inputs
+inputs = []
+cpx_pins = [board.A1, board.A2, board.A3, board.A4]
+
+for pin in cpx_pins:
+    cpx_pin = DigitalInOut(pin)
+    cpx_pin.direction = Direction.INPUT
+    cpx_pin.pull = Pull.UP
+    inputs.append(cpx_pin)
+
+#  NeoPixel colors
+GREEN = (0, 255, 0)
+CYAN = (0, 255, 255)
+BLUE = (0, 0, 255)
+PURPLE = (180, 0, 255)
+
+#  debounce states for inputs
+state_A1 = False
+state_A2 = False
+state_A3 = False
+state_A4 = False
+
+#  array of NeoPixel colors
+colors = [GREEN, CYAN, BLUE, PURPLE]
+#  array of MIDI notes
+midi_notes = [60, 64, 67, 72]
+#  array of input states
+input_states = [state_A1, state_A2, state_A3, state_A4]
+
+while True:
+
+    #  iterate through colors, inputs and MIDI notes
+    for i in range(4):
+        #  reset the state of the input and send NoteOff msg
+        #  after the input is released
+        if inputs[i].value and input_states[i]:
+            input_states[i] = False
+            midi.send(NoteOff(midi_notes[i], 120))
+
+        #  if an input is pressed...
+        if not inputs[i].value and not input_states[i]:
+            #  change thhe colors of the NeoPixels
+            pixels.fill(colors[i])
+            pixels.show()
+            #  send the NoteOn msg
+            midi.send(NoteOn(midi_notes[i], 120))
+            #  update input state
+            input_states[i] = True