diff --git a/code.py b/code.py index 7f8ab20..b0c7eee 100755 --- a/code.py +++ b/code.py @@ -2,8 +2,7 @@ # # 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. +# 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 @@ -21,6 +20,7 @@ import board import busio import analogio import digitalio +import math import usb_midi import adafruit_midi from adafruit_midi.timing_clock import TimingClock @@ -29,55 +29,69 @@ 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) +# Midi output settings +midi_channel = 1 # Target midi channel to write to +cc = 1 # Target Control Change number - Expression Pedal +cc_min = 0 # Minimum desired CC output - 0 - 127 +cc_max = 127 # Maximum desired CC output - 0 - 127 -exp_pedal_calibration_percent = 80 # Required percentage of expression pedal movement for calibration +# Expression pedal settings +logarithmic = True # Expression pedal logarithmic or linear. Set to False for linear +log_base = 100 # This value changes the feel of the log curve + +# Required percentage of expression pedal movement for calibration +exp_pedal_calibration_percent = 80 # 0 - 100 # 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 +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 +usb_midi = adafruit_midi.MIDI( + midi_out=usb_midi.ports[1], out_channel=midi_channel - 1) # 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 + if logarithmic: + scaled_val = math.log(exp_val, log_base) # Apply logarithmic scaling + return int((((scaled_val - math.log(exp_min, log_base)) * (cc_max - cc_min)) / (math.log(exp_max, log_base) - math.log(exp_min, log_base))) + cc_min) + else: + return int((((exp_val - exp_min) * (cc_max - cc_min)) / (exp_max - exp_min)) + cc_min) +# Initialise variables +offset = 1e-6 # Small offset to avoid log(0) error + +# Set these to reverse thresholds to enable calibration +exp_min = 65535 +exp_max = offset + +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 exp_previous = exp.value +if exp_previous == 0: + exp_previous = offset + +# main loop while True: - exp_current = exp.value + exp_current = exp.value + if exp_current == 0: + exp_current = offset - # 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 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)) \ No newline at end of file + # 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)) \ No newline at end of file