ash/Pi-Pico-ExpressionPedal2Midi
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Ashley Strahle
2021-01-30 20:16:39 +10:00
parent 0a9823cea3
commit fc4584fdce
1 changed files with 20 additions and 13 deletions
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33
main.py
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@@ -6,27 +6,30 @@ import time
# Constants
ControlChange = 0xb0
# Devices
exp = machine.ADC(Pin(26)) # Expression pedal device on pin 31
uart = machine.UART(1, 31250) # UART Midi device on pin 6
led = machine.Pin(25, Pin.OUT) # Pico onboard led
# 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 = 0 # Minimum desired CC output
cc_max = 97 # Maximum desired CC output (only want fader to go to unity gain - hence not 127)
# Devices
exp = machine.ADC(Pin(26)) # Expression pedal device on pin 31
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
exp_min = 65535
exp_max = 0
exp_calibration_threshold = 40000 # This is the minimum amount of change required successful for calibration
cc_previous = 0
cc_current = 0
# This function translates the expression pedal value to the equivalent CC value
def translate(exp_val):
if exp_max - exp_min > 40000:
if exp_max - exp_min > exp_calibration_threshold:
ret = int((((exp_val - exp_min) * (cc_max - cc_min)) / (exp_max - exp_min)) + cc_min)
else:
return 0
@@ -36,17 +39,21 @@ def translate(exp_val):
else:
return 0
exp_previous = exp.read_u16()
while True:
exp_current = exp.read_u16()
cc_current = translate(exp_current)
if exp_current > exp_max:
exp_max = exp_current
elif exp_current < exp_min:
exp_min = exp_current
if abs(exp_current - exp_previous) > 800:
exp_previous = exp_current
cc_current = translate(exp_current)
if exp_current > exp_max:
exp_max = exp_current
elif exp_current < exp_min:
exp_min = exp_current
if cc_current != cc_previous:
if cc_current != cc_previous:
led.value(1) # Turn led on
uart.write(ustruct.pack("bbb",ControlChange + midi_channel - 1,cc,cc_current))
led.value(0) # Turn led off
cc_previous = cc_current
print("Writing Midi Channel: {}, ControlChange: {}, Value {}. Exp Pedal: cur: {}, min: {}, max: {}".format(midi_channel, cc, cc_current, exp_current, exp_min, exp_max))
print("Writing Midi Channel: {}, ControlChange: {}, Value {}. Exp Pedal: cur: {}, min: {}, max: {}".format(midi_channel, cc, cc_current, exp_current, exp_min, exp_max))
time.sleep(0.05)