StringTheory Software

This is the source code for StringTheory. It’s written using the Arduino programming environment and leverages a couple of widely-available Arduino libraries (MIDI & EEPROM).

To program your ATMega328P-PU IC, you’ll need the programming environment and an Arduino programmer (you can use a cheap Arduino Nano to do this). DON’T FORGET TO WRITE A BOOTLOADER TO THE CHIP FIRST!

The code is open-source. In recognition of his work Jan Ostman, the original developer of the code upon which this version is based, shares the proceeds from the sale of every PCB, panel, chip, kit or completed module that we sell.

Feel like modding it? Get stuck in and hack away! We’d love to see (and hear!) what you come up with!

Latest version

This is the latest version of the software, current from 5th August 2018.


  • Note on/note off code refactored and improved
  • MIDI offset function added to MIDI Learn mode

Download the StringTheory V2 source code here (.zip file)

Previous versions

Download the StringTheory V1 source code here (.zip file)