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https://github.com/ashstrahle/Pi-Pico-ExpressionPedal2Midi.git
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74 lines
2.6 KiB
Markdown
74 lines
2.6 KiB
Markdown
# [Pi-Pico-ExpressionPedal2Midi](https://github.com/ashstrahle/Pi-Pico-ExpressionPedal2Midi) now with added USB
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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.
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Midi channel, CC number, and maximum and minimum values are customisable. Your choice of logarithmic or linear expression pedal feel.
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The expression pedal is automatically calibrated. At startup, simply move your pedal from minimum to maximum. The values are determined accordingly, and CC messages will start being sent.
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## Recipe
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### Ingredients
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- Raspberry Pi Pico (loaded with MicroPython)
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- ¼” jack TRS socket
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- 5 pin DIN midi socket<sup>1</sup>
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- 10Ω resistor<sup>1</sup>
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- 33Ω resistor<sup>1</sup>
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<sup>1</sup> Required only if using midi port (non-usb)
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Optional: breadboard, 40 pin male headers, pin cables, scotch whisky
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Power source:
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Either USB or 3xAA battery holder
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### Method
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1. Download [CircuitPython](https://circuitpython.org/board/raspberry_pi_pico/) and install on your Pico.
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2. Download [CircuitPython Libraries](https://circuitpython.org/libraries) and copy ```adafruit_midi``` folder to ```lib``` folder on your Pico.
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3. Customise the midi settings in ```code.py```. Season to taste
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4. Copy ```code.py``` to your Pico.
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<i>Now for the stuffing:</i>
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#### Expression Pedal Jack
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The expression pedal is connected to ADC0 on the Pico.
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5. Connect the jack sleeve to Pico ground pin (any of 3, 8, 13, 18, 23, 28, or 33)
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6. Connect the jack ring to Pico pin 31 (ADC0)
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7. Connect the jack tip to Pico pin 36 (3V3 OUT)
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If you're only using USB, you're done!
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<i>Otherwise...</i>
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#### Midi Port
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Midi messages are sent simultaneously to USB and UART1. If you wish to connect your Pico to a Midi port, proeceed with the following.
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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
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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
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10. Connect a Pico ground pin (any of 3, 8, 13, 18, 23, 28, or 33) to pin 2 of your midi socket
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Jubilations, you’re done.
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Ashley Strahle
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https://github.com/ashstrahle
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