My day job is in software, so this is the fun part for me. The Arduino sketch does 2 things: read the CD4021 shift registers & outputs MIDI notes. I know the pedalboard covers notes C2 - G4, but what does that translate to in MIDI.

After asking the mighty Google, I learnt that C2 is MIDI note 36, up to G4 which is MIDI note 67.

Using the Arduino MIDI library, a simple function takes care of this:

MIDI.sendNoteOn(note, velocity, channel)
MIDI.sendNoteOff(note, velocity, channel)

The Arduino sketch turned out to be pretty simple: Read the switches, if the value has changed from the last time they were read, send the MIDI command.

The sketch is included in the Github repo.

Next step is to build the circuit on a breadboard to prove if this design can work!