TB2 and RED kits are available in the store

Groovesizers are kit-built DIY sequencers and synths. They’re open-source instruments, which means firmware for the Groovesizers can be freely examined, shared and changed in the beginner friendly Arduino IDE.

Theremon (coming soon)


TB2With the Quartet firmware, the TB2 is a 4 voice paraphonic wavetable synth shield for the Arduino Due development board. The TB2 features 2 oscillators per voice, an ADSR envelope, LFO, digital filter,  arpeggiator, as well as a 16-step sequencer.

For sound generation, the TB2 makes use of the pair of 12-bit DACs built into the Arduino Due’s 32 bit ARM processor. The TB2 uses an SD card for storing patches and sequences, and it also allows the user to load single cycle waveshapes for the two oscillators and the LFO.

The Attack! firmware turns the TB2 into a 6 voice drum machine with a 32-step sequencer.


The RED is a 16-step MIDI sequencer and granular synth.

Groovesizer RED

It’s a great kit for first-time DIY builders with a low parts count and clear building instructions.

In spite of its straightforward design, the RED features a number of advanced sequencing features such as various bank and pattern playback modes, note entry quantized to preset and user defined scales, 32 memory locations for storing patterns, and MIDI sync in and out.

Multiboard (MB)

The RED’s big brother is the Groovesizer MB.

NOTE: we no longer offer kits for the MB, but all the design and firmware files are available on these pages if you want to attempt building one for yourself.

Groovesizer MB
Groovesizer MB

It can be transformed into a number of different instruments (sequencer, synth, drum machine, or midi controller) thanks to a growing range of firmware options.

Already available are the Alpha (32-step sequencer and 3 voice monosynth), Bravo (4-voice, 8-bit drum machine), Delta (32-step sequencer and granular synth), Golf (32-step, 12-track MIDI drum sequencer), Foxtrot (clip and scene launcher for Abelton Live), along with a template for developing one’s own firmware.

Here’s a jam with a Groovesizer RED synced to a Groovesizer Golf triggering drum sounds on a Zoom MRT-3.

The Groovesizer philosophy is twofold. The first is to provide a platform suitable for beginners to learn about the design and coding of microprocessor based electronic musical instruments. The second is to create DIY instruments with a unique voice and feature set, and that are capable of holding their own in the studio or on stage.