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This is a work in progress

A DIY polyphonic guitar tuner pedal. With it you can check the tuning of all the strings with a single strum, saving you time when you need it most. Very useful for playing live!


This work has been developed by Sergio Sánchez as his Bachelor's Thesis, with David Estevez as his advisor. The Thesis itself can be downloaded here (in Spanish).

The work has three main parts:

  • A preeliminary study of the guitar signal to decide the best analysis technique for the pedal. This study was made in Matlab and the sources for the study can be found in the MATLAB Analysis folder.
  • A software implementation of the polyphonic tuner to validate the algorithms prior to the hardware implementation. This code is written in Python and contained in the Software tuner folder.
  • A hardware implementation (i.e. the pedal itself). The firmware for the device is stored in the Polytuna Teensy Edition folder. The schematics can be found in the Thesis document. The full circuit and the PCB KiCad project can be found at Polytuna KiCad folder.

Some pictures of the prototype: (HD images can be found here) pic1 pic2 pic3 pic4 pic5 pic6 pic7 pic8

The last completed step was the creation of a first PCB prototype, shown on the images, that's fully functional as a tuner. Currently the work is focused on improving the display software capabilities to ensure it's easily readable.


  • Sergio Sánchez