This is a footswitch using TMK's keyboard firmware for a Teensy 2. As it's seen by the OS as a keyboard it should work on any computer that supports USB keyboards.

• 1 Normally open footswitch. I used an M-GEAR sustain pedal for a keyboard.
• 1 Teensy 2
• 1 Mini-USB cable long enough to run back to your computer.

1. Disassemble your footswitch
2. Disconnect the original cable.
3. Remove any unnecessary switches and circuitry.
4. Connect the switch to B0 and B1 of your Teensy.
5. Fix your Teensy to the inside of your pedal.
6. Run your USB cable from the Teensy out of the pedal housing.
7. Clone the TMK keyboard firmware from https://github.com/tmk/tmk_keyboard.git
8. cd into the checked out directory.
9. Add this repo as a submodule with git submodule add https://github.com/jonhiggs/fs01.git keyboards/fs01.git
10. make the code.
11. Use the 'Teensy App' to program the hex file to your Teensy.
12. Enjoy your new footswitch.

By default the switch sends L_GUI which on OS X is the Command key. You can change the key that is sent in keymap_plain.c.