Dust off that GBA: it’s a groove box now. Stepper is a free and open source 16-step sequencer with full access to the onboard sound engine and per-trigger parameter locks, Elektron-style. (And this pairs well with Elektron gear, as the developer shows.)

I’m late to the party on this one, but I’m definitely up for getting the GBA running again with something new. And while trackers tend to be the preferred musical paradigm of Game Boy artists, the design here has plenty to recommend it.

And yes, that is a Nintendo 3DS the developer photographed, but the app itself uses the GBA sound engine, GBA controls – the ROM file is GBA. (There’s both a .gba download and a .cia for the Virtual Console on devices like the one pictured.)

Updated: see below for an authentic GBA image! (Ooh, and it does look nice. Okay, now considering a flash cart.)

You’ll need to hack the Nintendo hardware in order to run either solution. Jailbreaking the newer 3DS is easier; you need specialized hardware for a GBA. See this guide to 3DS homebrew or this massive guide to GBA homebrew.

  • Per-trigger parameterization across the whole engine
  • 4 DMG sound channels – 2 square wave, 1 custom wave, 1 noise
  • 4 banks of 8 patterns with live performance queuing (one pattern queue)
  • Quick access via GBA controls: move around with D-pad, B for toggling / queuing / pattern & bank switching, hold A for trigger parameters, L/R to change notes and values
  • Duty cycle, envelope, and sweep parameter controls
  • Programmable waves – sine, saw, square, random
  • Noise with two modes

STEPPER: A Toy 16-step Sequencer for the Game Boy Advance

Free and open source; see the Git archive. (hey, how many of us do you expect will wind up self-hosting to avoid our code getting ripped off by AI?)


That GBA engine is really no slouch – a familiar architecture for Nintendo gaming fans, but with enough control to hold up as a modern instrument.

So there’s no direct sync or MIDI support, if you’re wondering. As this dev recommends, a good starting place would be trash80’s excellent ArduinoBoy project – and messing around with that could be a fun project in itself:


But, come on, you know how to make sync work without cables. You set the tempo, you hit play on both devices. (They do point out that you might need to use a fractional bpm on the other box.)

The developer was inspired by – and uses the GBA with – Elektron gear. All images courtesy badd10de.

Creator badd10de has a bunch of other neat projects, including various Bitwig, Polyend, and Elektron things on their YouTube plus some pixel art. And here’s a lovely track they made with the setup GBA/Stepper + Digitakt.

More code made by humans, by hand.