The Raspberry Pi is no stranger to the world of music having become a popular choice for many artists looking to create digital synths. Today we’re taking a look at another cool synth project that uses a Raspberry Pi known as Groc . It’s shown using a Raspberry Pi Compute Module 4 (CM4) in the demo and was created by a team named Oddment Audio.

According to a recent post shared by the team to Reddit, Groc is still a work in progress. That may be the case but enough progress has been made to pull off a demo that we think is cool enough to share. It has all of the tools necessary to draft something from scratch including a display with an interface.

In the demo video, we get a good look at the module and how it operates. There are 18 center-lit knobs that glow with blue LEDs. These are used to alter and mix sound effects on the synth. The video shows a simple loop made from an audio sample of a guitar riff. The knobs allow you to adjust parameters like the attack, decay, release and sustain speeds.

These illuminated knobs are rotary encoders that can also be pressed as a button. They are mounted to a custom PCB that also sports a speaker and small screen. The PCB is connected to the GPIO of a CM4, specifically the GPIO breakout of the CM4 IO board. This means that a CM4 is not essential for the synth to operate. We could also use this board and code on a Raspberry Pi 4, or even a Raspberry Pi Zero 2 W.

As far as software goes, Groc is designed to use a custom graphic interface. This outputs a visual GUI to the display screen showing critical elements like an audio visualizer as well as indicators for what the knobs are changing and to what degree. You can get a good look at the GUI layout in the demo video.

If you want to get a closer look at this Raspberry Pi project , check out the original post shared to Reddit for more details. Be sure to follow Oddment Audio for future updates on this cool custom synth.