ash/Pi-Pico-ExpressionPedal2Midi
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Ashley Strahle
2021-01-30 21:16:23 +10:00
parent f2fdcd1e67
commit b058144055
1 changed files with 7 additions and 4 deletions
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11
main.py
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@@ -12,7 +12,7 @@ cc = 68 # Target Control Change number - this is for Behringer X32 Matrix 5
cc_min = 0 # Minimum desired CC output
cc_max = 97 # Maximum desired CC output (only want fader to go to unity gain - hence not 127)
exp_calibration_threshold = 40000 # This is the minimum amount of change required successful for calibration
exp_pedal_calibration_percent = 80 # Required percentage of expression pedal movement for calibration
# Devices
exp = machine.ADC(Pin(26)) # Expression pedal device on pin 31
@@ -20,10 +20,13 @@ uart = machine.UART(1, 31250) # UART Midi device on pin 6
led = machine.Pin(25, Pin.OUT) # Pico onboard led
# Initialise variables
# Set these to reverse thresholds to enable self calibration
# 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)
@@ -37,7 +40,7 @@ while True:
exp_current = exp.read_u16()
# Only process if the change ratio is greater than the possible number of CC values
if abs(exp_current - exp_previous)/exp_max > 1/(cc_max - cc_min):
if abs(exp_current - exp_previous)/exp_max > cc_ratio:
if exp_current > exp_max:
exp_max = exp_current
elif exp_current < exp_min:
@@ -46,8 +49,8 @@ while True:
# Only send midi when calibration threshold has been reached
if exp_max - exp_min > exp_calibration_threshold:
cc_val = translate(exp_current)
led.value(1) # Turn led on
cc_val = translate(exp_current)
uart.write(ustruct.pack("bbb",ControlChange + midi_channel - 1,cc,cc_val))
led.value(0) # 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))