Discover a universal musical instrument / modular groovebox



Trinity is a universal musical instrument and original sounding modular groovebox. It can function as any type of digital synthesizer, sequencer, controller, arpeggiator, or almost anything that can be programmed into a micro-controller.


Trinity is designed to be connected and combined with other Trinities of different functions in a chain so that you can create your own music-making environment. It is ready to communicate with the outer world via MIDI and different sync and CV methods using MIDI Bastl. We are musicians passionate about exploring new fields of sonic experience – we already developed 4 different instruments for Trinity, which work great together. They are sequencer, drum synthesizer, polyphonic synthesizer, and monophonic FM synthesizer… and there are many more to come!


  • simple interface which makes it an intuitive musical instrument
  • available assembled or as a soldering kit
  • MIDI native (note, CC), MIDI jack and almost endless sync possibilities using MIDI Bastl
  • software reprogrammable with Arduino (breakout for standard FTDi USB)
  • hardware expandable and hackable – including breakouts for sensors or more buttons
  • chain connectors for sharing power, audio, and communication with more Trinity/Bastl instruments
  • user memory for storing presets and patterns (exportable, transferable)
  • stylish laser-cut replaceable enclosure with instrument labels
  • adjustable volume
  • mono, 16385Hz, 14 bit – double PWM sound generation
  • TRS Jack 3.5mm audio output able to drive headphones
  • powered from 9V battery or 9V positive polarity power supply (2.1 mm) or from the Trinity chain (use switch to select)
  • running Mozzi library and Bastl library for Arduino


The true power of Trinity reveals when more instruments are connected in a chain that shares communication (MIDI), Audio line, and power.

COMMUNICATION: SQNCR can sequence 3 different Trinity instruments via MIDI protocol, which is ideal for live sequencing. All instruments have MIDI input, which reads note and CC values. (We plan to make a CC automation sequencer and sensor boards sending CC.)

AUDIO: The chain connectors also share an audio line which simply works as a passive mixer, so all instruments can be mixed directly on Trinities themselves using the volume knobs, and audio can be taken out by the rightmost jack. You can also take the audio from each device separately.

POWER: The chain also shares power, so you need only one power adaptor to power the whole system. The Instruments can be powered from batteries in the chain as well.

Technical details

Trinity is as much a finished musical instrument as an empty canvas. It is open for any sort of hacks, both hardware and software. You can hack the existing software or write your own synth software from scratch using the Mozzi library for sound output. Because Trinity is based on Arduino, you can use the whole world of it to interface literally anything with it. Hardware hackability means that you can connect sensors or motors to it or sync it to any device. The software and examples are written in a structured form so you can read and change them easily.

Beyond Trinity

The field of our sonic fantasies lies beyond the algorithmically synthesized digital stuff. We are working on the development of digitally controlled analog circuitry, on mechanical output through motors and high voltage switchers, but also in implementing different sensoric / weird ways of performing. This all compatible with the Trinity chain.

List of software ideas for Trinity

  • xor synth 6 voice polyphonic synth playable by MIDI (almost ready)
  • mystery drone synth
  • magic table oscillator synth
  • algorithm+random synth
  • MIDI arpeggiator
  • sequencer for single Trinity instrument
  • automation sequencer / LFO
  • …and many more…


  • sync sequencer with GameBoy Nanoloop (by led and by MIDI bastl) – done
  • sync with Korg Volca by MIDI Bastl – done
  • trigger analog drum sounds from SQNCR or Drum – done
  • randomizer – done
  • photo resistor (LDR) controlling parameters of synth – done
  • exchange sounds between the same instruments – done for POLY
  • cv and gate to MIDI CC and note by MIDI bastl – planned
  • very nice assembly video by Daniel Baum + another of his videos with Trinity


  • casing and graphic layout was designed by Anymade Studio
  • PCB designed in Fritzing
  • using Arduino IDE to develop and upload the software
  • using Mozzi library for Arduino
  • using MIDI library for Arduino
  • PCB and software by Václav Peloušek
  • developed by Bastl Instruments

Legal statement

  • software is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License view
  • hardware licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License view
  • CE a RoHS compliant