Florian Loretan bought an old Bontempi keyboard, but it stopped working. Instead of consigning it to the scrap heap, he ended up on a journey to create a custom polyphonic Teensy-based synth, with the only remaining part of the original keyboard being the keys and matrix.
![](/wp-content/uploads/2024/02/bontempi-1.png)
In addition to the Teensy 3.1, an Audio Adaptor Board is used, though not in the typical stacked orientation. Multiplexers handle the keyboard matrix and the custom potentiometer-based interface. More detail on the electronics can be found in a separate video, as can specifics on building the case, and a demo of everything together can be seen below. The source code, which is still a work in progress, can be found on GitHub.