Sid Rockett's Arena Digitalis Turns the Arduino Nano R4 Into a "Glitch Machine" Granular Synth

Musician and maker Sid Rockett has released a "glitch machine" granular synthesizer built around the newest entry in the Arduino Nano board family, the 32-bit Arduino Nano R4: the open source Arena Digitalis.

"Arena Digitalis is a high-performance, real-time granular audio processor built on the Arduino Nano R4's 32-bit architecture," Rockett explains of his creation. "Unlike standard digital delays, this device treats incoming audio as a 'physical matter,' slicing your input signal into tiny fragments (grains) and reassembling them to create everything from lush ambient washes to jagged, bit-crushed glitches."

The synth, brought to our attention by the Arduino team, offers 12-bit audio input and output capabilities with a dual-state digital signal processor (DSP), intelligent buffer monitoring, input safety monitoring, and support for "grain" sizes from 50 to 1,500 samples. If all that sounds like a little much for an Arduino Nano, you may have missed the launch of the Arduino Nano R4 — a dramatically upgraded entry in the range that swaps out the traditional eight-bit microcontroller for a much more powerful 32-bit Renesas RA4M1 chip.

How the input is transformed into the output depends on how the controls are manipulated: as well as adjusting the grain size and playback speed, the synth can be set to balance a "dry/wet" mix, run the audio through a smooth low-pass filter or gritty bit-crushing downsampling filter, "spray" audio by jumping around the buffer at random, adjust the grain shape from "clicky" to "smooth," quantize the pitch, add a tremolo effect via a low-frequency oscillator, and reverse playback.

Schematics, Gerber board production files, a bill of materials, and source code for the firmware are all available on the project's GitHub repository , under an unspecified open source license.