whammy-arduino

A MIDI controller for the Digitech Whammy IV effects pedal.

Demo on Youtube

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The implementation currently provides these modes:

• Active (LED blue): Ramp towards toe-down when active, ramp towards heel-down when inactive.
• Waves (LED white):
  • Sine: ramp up and down following a nice smooth sine wave /‾\_/‾\_
  • Sawtooth up: linear ramp up, immediate return to zero ////
  • Sawtooth down: linear ramp down, immediate return to maximum `\\
  • Triangle: linear ramp up and down /\/\/
• Sequencer (LED red):
  • Square _‾_‾
  • "Map of the Problematique"
  • Octaves -2, -1, 0, +1, +2
  • Random sequence
• Scale (LED yellow): Random pedal positions quantised to a musical mode (Phrygian, Lydian, etc)
• Random position (LED green): unquantised, random pedal positions.
• 'Chaos' (LED cyan): random selection from the above modes.

Hardware

• Wiring diagram here
• Arduino Nano clone
• 3 momentary buttons
• One linear potentiometer
• MIDI port
• RGB LED
• A few resistors, wire, case, etc.

Configuration config.h

The following values must be set correctly or your pedal will not work!

LED_COMMON_PIN

Set to LED_COMMON_CATHODE if your LED has a common cathode.
Set to LED_COMMON_ANODE if your LED has a common anode.

PEDAL_HARDWARE

Must match the model of the Whammy you are connecting to.

Set to WHAMMY_IV if connecting to a Whammy IV.
Set to WHAMMY_DT if connecting to a Whammy DT.

Other whammy models may also work but will need to have their MIDI configurations added - contact me if you want a particular pedal to be supported and I'll try and add it.

PIN_...

All values with the PIN_ prefix must correctly match the Arduino pins that you wire the LED and controls.

Options

All other settings in config.h have default values which you can edit to your preference:

• MAX_BRIGHTNESS
• MAX_TEMPO
• MIN_TEMPO
• DEFAULT_PATCH
• DEFAULT_POSTION

Controls

On/off: activate the pedal.
Modifier + On/off: Toggle between momentary and latching activation. Momentary/latching mode persists in EEPROM between sessions so you don't need to change it every time.

Mode: move to the next pedal mode.
Modifier + Mode: move to previous mode.

Tempo potentiometer: Turn to change speed of all pedal functions.
Modifier + Tempo potentiometer: Limit the maximum range of the pedal position for tasteful vibrato-like operation ^{[citation needed]}.

Modifier: Tap to change the musical mode used in 'quantized scale' mode.

In all modes, the LED brightness indicates the effective position of the pedal - brighter means toe-down, darker means heel-down.

Troubleshooting

A couple of things to check if the pedal isn't working as expected:

• Check the Configuration section and ensure that all values correctly match your hardware.
• Check the MIDI settings on your Whammy pedal and ensure it is listening on channel one. If you're not sure, set your Whammy channel to 'omni' so it listens on all MIDI channels.
  On the Whammy IV this is done by holding down the footswitch while powering the pedal on. A light should start flashing beside one of the modes - rotate the knob until the light moves to the top left (Harmony Octave Up/Down) setting. Press the footswitch again to confirm.
  Other models may work differently - check the manual for your particular Whammy version.

monitor.pd

If you want to work on this project without going mad from constant atonal wee-woo noises, open monitor.pd with Pure Data to see a visualisation of the MIDI messages instead.

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This project kept me busy while isolating with Covid 19 in April 2022. The illness provided some gnarly headaches and this project did not help with that whatsoever. Fun though. ``