CircuitPython, adafruit_midi rewrite. USB capable (#4)

code.py

@@ -0,0 +1,83 @@
+################################################################################
+#
+# Pi-Pico-ExpressionPedal2Midi
+#
+# Connect an expression pedal to ADC0, a midi out socket/cable to UART1 if not
+# using USB midi. Midi messages are sent simultaneoulsy to UART1 and USB. 
+# Set desired midi channel, change control, and maximum and minimum values
+#
+# Upon run/power on, move expresson pedal from maximum to minimum to calibrate
+# your pedal. CC commands will immediately start sending once calibrated.
+#
+# Ashley Strahle
+# https://github.com/ashstrahle
+#
+################################################################################
+
+import sys
+import struct
+import time
+import board
+import busio
+import analogio
+import digitalio
+import usb_midi
+import adafruit_midi
+from adafruit_midi.timing_clock import TimingClock
+from adafruit_midi.note_on import NoteOn
+from adafruit_midi.note_off import NoteOff
+from adafruit_midi.pitch_bend import PitchBend
+from adafruit_midi.control_change import ControlChange
+
+# Midi settings
+midi_channel = 1 # Target midi channel to write to
+cc = 68 # Target Control Change number - this is for Behringer X32 Matrix 5
+cc_min = 20 # Minimum desired CC output
+cc_max = 97 # Maximum desired CC output (only want fader to go to unity gain - hence not 127)
+
+exp_pedal_calibration_percent = 80 # Required percentage of expression pedal movement for calibration 
+
+# Devices
+led = digitalio.DigitalInOut(board.LED)
+led.direction = digitalio.Direction.OUTPUT
+exp = analogio.AnalogIn(board.GP26) # Expression pedal device on pin 31
+uart = busio.UART(tx=board.GP4, rx=board.GP5, baudrate=31250, timeout=0.001) # UART Midi device on pin 6
+uart_midi = adafruit_midi.MIDI(midi_out=uart, out_channel=midi_channel - 1)
+usb_midi = adafruit_midi.MIDI(midi_out=usb_midi.ports[1], out_channel=midi_channel - 1)
+
+# Initialise variables
+# Set these to reverse thresholds to enable calibration
+exp_min = 65535 
+exp_max = 1
+
+exp_calibration_threshold = int(abs(exp_max - exp_min) * exp_pedal_calibration_percent / 100)
+cc_ratio = 1/(cc_max - cc_min) # Calculate number of possible CC values
+
+# This function translates the expression pedal value to the equivalent CC value
+def translate(exp_val):
+  ret = int((((exp_val - exp_min) * (cc_max - cc_min)) / (exp_max - exp_min)) + cc_min)
+  if ret > 0:
+    return ret
+  else:
+    return 0
+
+exp_previous = exp.value
+while True:
+  exp_current = exp.value
+
+  # Only process if the change ratio is greater than the possible number of CC values
+  if abs(exp_current - exp_previous) / exp_max > cc_ratio: 
+    if exp_current > exp_max:
+      exp_max = exp_current
+    elif exp_current < exp_min:
+      exp_min = exp_current
+    exp_previous = exp_current
+
+    # Only send midi when calibration threshold has been reached
+    if exp_max - exp_min > exp_calibration_threshold: 
+      led.value = True # Turn led on
+      cc_val = translate(exp_current)
+      uart_midi.send(ControlChange(cc, cc_val))
+      usb_midi.send(ControlChange(cc, cc_val))
+      led.value = False # Turn led off
+      print("Writing Midi Channel: {}, ControlChange: {}, Value {}. Exp Pedal: cur: {}, min: {}, max: {}".format(midi_channel, cc, cc_val, exp_current, exp_min, exp_max))

docs/README.md

@@ -1,10 +1,10 @@
-# Pi-Pico-ExpressionPedal2Midi
+# [Pi-Pico-ExpressionPedal2Midi](https://github.com/ashstrahle/Pi-Pico-ExpressionPedal2Midi)
 
 ![](/docs/Pi-Pico-ExpressionPedal2Midi.gif)
 
 ![](/docs/Pi-Pico-ExpressionPedal2Midi2.jpeg)
 
-This is a Raspberry Pi Pico MicroPython project that takes an expression pedal input via a TRS 1/4" jack connected to ADC pins on the Pico, and outputs respective Midi CC messages via UART.
+This is a Raspberry Pi Pico CircuitPython project that takes an expression pedal input via a TRS 1/4" jack connected to ADC pins on the Pico, and outputs respective Midi CC messages simultaneously to UART and USB.
 
 Midi channel, CC number, and maximum and minimum values are customisable.
 
@@ -16,43 +16,48 @@ The expression pedal is automatically calibrated. At startup, simply move your p
 
 - Raspberry Pi Pico (loaded with MicroPython)
 - ¼” jack TRS socket
-- 5 pin DIN midi socket
-- 10Ω resistor
-- 33Ω resistor
+- 5 pin DIN midi socket<sup>1</sup>
+- 10Ω resistor<sup>1</sup>
+- 33Ω resistor<sup>1</sup>
 
-Optional: breadboard, 40 pin male headers, pin cables, scotch
+<sup>1</sup> Required only if using midi port (non-usb)
+
+Optional: breadboard, 40 pin male headers, pin cables, scotch whisky
 
 Power source:
 Either USB or 3xAA battery holder
 
 ### Method
 
-1. Customise the midi settings in main.py. Season to taste
-2. Upload to your board using Thonny, or your favorite IDE.
+1. Download [CircuitPython](https://circuitpython.org/board/raspberry_pi_pico/) and install on your Pico.
+2. Download [CircuitPython Libraries](https://circuitpython.org/libraries) and copy ```adafruit_midi``` folder to ```lib``` folder on your Pico.
+3. Customise the midi settings in ```code.py```. Season to taste
+4. Copy ```code.py``` to your Pico.
 
-Now for the stuffing:
+<i>Now for the stuffing:</i>
 
-#### Midi port
-
-![](/docs/Pi-Pico-ExpressionPedal2Midi4.jpeg)
-
-Midi messages are sent via UART1. Here’s where we need the resistors to protect the board and your midi device. 
-
-3. Connect a 10Ω resistor to pin 6 on the Pico (UART1 TX). T’other end of the resistor to pin 4 of your midi socket
-4. Connect a 33Ω resistor to pin 36 on the Pico (3V3 OUT). T’other end of the resistor to pin 5 of your midi socket
-5. Connect a Pico ground pin (any of 3, 8, 13, 18, 23, 28, or 33) to pin 2 of your midi socket
-
-You’re done here, next…
-
-#### Expression pedal jack
+#### Expression Pedal Jack
 
 ![](/docs/Pi-Pico-ExpressionPedal2Midi3.jpeg)
 
 The expression pedal is connected to ADC0 on the Pico.
 
-6. Connect the jack sleeve to Pico ground pin (any of 3, 8, 13, 18, 23, 28, or 33)
-7. Connect the jack ring to Pico pin 31 (ADC0)
-8. Connect the jack tip to Pico pin 36 (3V3 OUT)
+5. Connect the jack sleeve to Pico ground pin (any of 3, 8, 13, 18, 23, 28, or 33)
+6. Connect the jack ring to Pico pin 31 (ADC0)
+7. Connect the jack tip to Pico pin 36 (3V3 OUT)
+
+If you're only using USB, you're done! 
+
+<i>Otherwise...</i>
+#### Midi Port
+
+![](/docs/Pi-Pico-ExpressionPedal2Midi4.jpeg)
+
+Midi messages are sent simultaneously to USB and UART1. If you wish to connect your Pico to a Midi port, proeceed with the following.
+
+8. Connect a 10Ω resistor to pin 6 on the Pico (UART1 TX). T’other end of the resistor to pin 4 of your midi socket
+9. Connect a 33Ω resistor to pin 36 on the Pico (3V3 OUT). T’other end of the resistor to pin 5 of your midi socket
+10. Connect a Pico ground pin (any of 3, 8, 13, 18, 23, 28, or 33) to pin 2 of your midi socket
 
 Jubilations, you’re done.
 

legacy/README.md

@@ -0,0 +1,4 @@
+# Legacy Notes
+
+This is the original MicroPython version of Pi-PicoExpressionPedal2Midi, and only outputs to UART1 (no USB).
+Kept here for reference.