Merge pull request #3195 from adafruit/midi_breath

adding midi breath controller code

Author: BlitzCityDIY

QT_Py/MIDI_Breath_Controller/code.py

@@ -0,0 +1,98 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026 Liz Clark for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+'''QT Py RP2040 MIDI Breath Controller with BMP585'''
+import time
+import board
+import simpleio
+from adafruit_bmp5xx import BMP5XX
+from adafruit_seesaw import digitalio, neopixel, rotaryio, seesaw
+import usb_midi
+import adafruit_midi
+from adafruit_midi.control_change   import ControlChange
+from adafruit_midi.channel_pressure import ChannelPressure
+
+SEALEVELPRESSURE_HPA = 1013.25
+change_sense = 0.1 # change sensitivity
+low_press = 995 # lowest pressure reading range
+high_press = 1032 # highest pressure reading range
+
+i2c = board.STEMMA_I2C()
+bmp = BMP5XX.over_i2c(i2c)
+bmp.sea_level_pressure = SEALEVELPRESSURE_HPA
+
+seesaw = seesaw.Seesaw(i2c, addr=0x36)
+seesaw.pin_mode(24, seesaw.INPUT_PULLUP)
+button = digitalio.DigitalIO(seesaw, 24)
+encoder = rotaryio.IncrementalEncoder(seesaw)
+pixel = neopixel.NeoPixel(seesaw, 6, 1)
+pixel.brightness = 0.2
+
+midi = adafruit_midi.MIDI(midi_out=usb_midi.ports[1], out_channel=0)
+# CC message channels
+# last index is place holder for Channel Pressure message type
+messages = [1, 2, 7, 64, 0]
+# neopixel colors to associate with CC messages
+colors = [(255, 0, 0), (0, 255, 0), (0, 0, 255),
+          (255, 255, 0), (255, 0, 255)]
+
+pressure = 0
+mod_val1 = 0
+mod_val2 = 0
+effect_index = 0
+last_position = 0
+button_state = False
+pixel.fill(colors[effect_index])
+
+while True:
+    position = -encoder.position
+    if position != last_position:
+        # encoder changes midi CC message type
+        if position > last_position:
+            effect_index = (effect_index + 1) % len(messages)
+        else:
+            effect_index = (effect_index - 1) % len(messages)
+        pixel.fill(colors[effect_index])
+        last_position = position
+    if not button.value and not button_state:
+        pixel.fill((255, 255, 255))
+        # button press sends MIDI panic
+        panic = ControlChange(123, 0)
+        midi.send(panic)
+        # and turns sustain off
+        sus_off = ControlChange(64, 0)
+        midi.send(sus_off)
+        button_state = True
+    if button.value and button_state:
+        # reset neopixel to CC msg color
+        pixel.fill(colors[effect_index])
+        button_state = False
+    if bmp.data_ready:
+        # get pressure reading
+        pressure = bmp.pressure
+        # if the pressure has changed enough
+        # (adjust change_sense value at top to inc or dec)
+        if abs(pressure - mod_val2) > change_sense:
+            # map pressure reading to CC range
+            mod_val1 = round(simpleio.map_range(pressure, low_press, high_press, 0, 127))
+            #  updates previous value to hold current value
+            mod_val2 = pressure
+            # MIDI data has to be sent as an integer
+            modulation = int(mod_val1)
+            # possible midi messages determined by effect_index value:
+            # 1: modulation
+            # 2: breath controller
+            # 7: volume
+            # 64: sustain
+            # ChannelPressure(modulation)
+            if effect_index < 4:
+                # prep CC message with CC number and value as mapped pressure reading
+                modWheel = ControlChange(messages[effect_index], modulation)
+            else:
+                # prep Channel Pressure message with value as mapped pressure reading
+                modWheel = ChannelPressure(modulation)
+            # CC message is sent
+            midi.send(modWheel)
+            # print(modWheel)
+            # delay to settle MIDI data
+            time.sleep(0.001)