Skip to content
No description, website, or topics provided.
C++ Shell
Branch: master
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.

Gakken SX-150 Mk II - USB MIDI Mod


This project provides a standalone MIDI interface for the Gakken SX-150 synthesizer, and provides useable firmwares/sketches for the Arduino UNO r3 as well as the Leonardo or Pro Micro. The interface is simple to use: Simply plug the USB connector from your workstation to the MCU, and connect the remaining cables to your Gakken to provide CV.

As the interface itself is a fully class compliant USB MIDI device, the unit is fully standalone. No drivers are needed, and there is no client-side software to install or run- just plug and play! This interface has been successfully tested on macOS and iOS.

This project draws heavily from the work of:

Also of note is the wonderful SendMIDI utility, which is very useful for debugging.

A great deal of background information on the SX-150, including schematics, can be found in Documentation. More information, including wiring schematics for the interface, setup/build instructions, and more are forthcoming. The project is functional and very near complete, but remains a work in progress at the moment.

See it in action:


  • Tuning is way out of whack! (I'll need to bust out the multimeter and fiddle around) seems fixed in the Pro Micro version!
You can’t perform that action at this time.