Friends bragging lately about the quality of the sound of their drum machines?

Tell them you can make sounds lower fidelity than they can.

LUNCHBEAT is a 1-bit groovebox, making impossibly-dirty digital sounds, with a built-in step sequencer. While we await a proper DIY kit, it’s an ideal learning project: it’s nice and simple, has a low part count, everything you need as far as specs is available free to create your own, and it’s a good way to work out the basics of digital sound and sequencing.

And, really, if you need more than one bit to make music, what kind of musician are you? Go minimal.


Minimalistic groovemachine !
– 4 channels with 1 bit realtime generated sounds
– kickdrum, snare, hihat and bass
– 8 step sequencer
– MCU atmega328p@16MHz
– 8 LEDs with 74595 shift register
– 3 bit R2R resistor ladder DAC
– LM358 opamp as output buffer
– buttons, pots, resistors, wires, protoboard
– programmed in C
– compiled with avr-gcc
– uploaded with avrdude
sources released –

And it’s all hackable, especially if you know Arduino:

ISP6pin – hacker’s gate to unit’s microcontroller. Tweak the sound algorithms. Tweak the sequencer. Change unit’s purpose completely. Use the fact that Lunchbeat is the same thing as Arduino with 6 buttons, 5 pots, 8 LEDs on SPI shift register and 3-bit digital to analog converter. You can run Arduino sketches on it. From here it is up to you and your fantasy.


And you should be able to build this with your lunch money. I hope you do have lunch money and lunchtime, I mean, after plugging a cable from the back of your PC speaker to the front last week.


  • syntheticjuice

    Wonder what a PWM audio version of this would sound like…

  • Able archer 83

    That thing sounds rad. Pcb please.

  • Nolej

    Would it be possible to use an Arduino Uno as a programmer for the atmega? (And then just breadboard the parts together?)

    • Jan Cumpelik

      Definitely possible :)

    • Nolej

      One more question, is the PCB parts list applicable to the breadboard version?

    • Jan Cumpelik

      Yes, but PCB version uses some more parts (power supply, volume).

    • Lee Chaos

      …or with a Teensy, for class-compliant MIDI??! That’d be a bit awesome…

    • Jan Cumpelik

      I haven’t tried with any other microcontroller than 328p. But it should be portable easily.

  • Joshua Goran

    Reminds me of Noah Vawter’s One Bit Groovebox from back in the day…

  • Coy Austin Theobalt

    having a difficult time finding a 3-bit dac….. any ideas? Also is there an exact parts list somewhere?

  • RajaTheResidentTroll

    I want this.

  • thoughtswondersandthelike

    No, I don’t need more than one bit to make music, I want more than one. Now onto the device. All I can say is that it serves it’s purpose quite well if this is completely truthful.

  • Nate Donmoyer

    that breadboard version is gorgeous! so cool

  • JasoonS

    Ah soo cool!! I need learn how to make this stuff, Thanks for the inspiration!