Software Update/InstallDownloadsDetails

I sell on Tindie

The SquishBox is a synthesizer in a guitar pedal. It has 4 USB ports for you to plug in MIDI keyboards/controllers, stereo or headphone 1/4″ outputs, an LCD display, and two buttons for switching between patches and changing settings.

The SquishBox is designed to be inexpensive, easy to understand and modify, but still sound great. The brain of the SquishBox is a Raspberry Pi computer with an add-on sound card for high-quality audio. The sound engine is FluidSynth, an open-source software synthesizer that uses soundfonts, a versatile and widely-available sample-based sound format that can produce instruments from growly synths to perfect pianos. The interface is FluidPatcher – code written by Geek Funk Labs that allows you to create your own patches/banks, and even change the interface. You can buy one as a kit or fully assembled on Tindie.

Software Install/Update

The SquishBox comes with software preinstalled on its SD card. To update the software, or perform a fresh install on a custom build, the preferred method is to remotely log in to the SquishBox using ssh and run the install/update script by entering the following at the command line:

curl https://geekfunklabs.com/squishbox | bash

You may also install a complete operating system with the necessary software by writing the SquishBox OS Image below to the SD card using the Raspberry Pi Imager (choose the “Custom .img” option). The update script will, in general, provide a more up-to-date version of the software, and a much smaller download!



Schematics and a list of parts can be found in the Assembly Instructions above. The design files for the PCB can be downloaded from OSHPark. My project on Hackaday will show you how to build the SquishBox without the PCB, on single-sided perfboard. The source code for the SquishBox is publicly-available on GitHub, and includes a wiki explaining the API so you can modify or create your own interface.

The soundfont file format has been made publicly available, and as a result lots of software can use them and they’re widely available, both for purchase and free of charge/licensing. The quality of soundfonts available varies widely, and one person’s specific needs may differ from another’s, so I recommend searching out and trying as many as you can. I’ve tried to provide a healthy selection of free soundfonts in the OS image above. You can also easily modify soundfonts – not just the raw audio samples, but how they are played and even how they can be modulated by your controller – using various editors. I highly recommend Polyphone for this purpose. You can even create your own soundfonts from scratch!

The SquishBox comes with clutch of patches that are useful for playing in a variety of situations, but a big feature of the SquishBox is the ability to edit and create your own patches. The tutorial video series below will help you learn how to do this. Feel free to leave comments here or on YouTube as to how I can improve them or what other topics you’d like to see!