MidiWah v1.0

Arduino based bridge between the wah-wah (e.g. Dunlop GCB-95) and its potentiometer. Digitizes the potentiometer and feeds it via a digital potentiometer back to the circuit.

As a bonus, the digitized potentiometer signal can be outputted via MIDI OUT.

Contents

• Eagle schematic and PCB
• Arduino firmware

Eagle

Bill of materials

• Atmega168/328
• MCP4251
• 6N138

To be done.

Board render

To be done.

Arduino

The source can be found under firmware. It's build with Arduino 1.0.5, but newer versions should work too.

See the firmware/UsedLibraries.md for the libraries to install.

Firmware

To be done.

Configuration

The DIP switch on the PCB select the channel to which the MidiWah will respond

The firmware can be programmed via a few MIDI Control Change messages. Changes are only persisted when a save command is issued.

• CC 80 [0|1] — disable or enable calibration of the potentiometer. Replies with the same value.
• CC 81 [0|1] — disable or enable invertion of the potentiometer value. Replies with the same value.
• CC 82 [0-2] — select potentiometer program. Replies with the selected program, or the last one if program is invalid.
  • Program 0 is linear
  • Program 1 is logarithmic
  • Program 3 is first 50% from 0 to 127 and the next 50% from 127 to 0
• CC 83 [x] — save settings to EEPROM. The parameter x can be anything. Responds with same message.

License

See the LICENSE file (MIT license).