−MICROGROOVE

DIY GROOVEBOX IN YOUR POCKET

A wallet-sized groovebox that turns $30 of hardware and a 3D printer into a four-track acid powerhouse — three mono/poly 303 voices, eight lanes of 808 & 909 drums, and a sampler that records the room or the machine itself.

PRINT IT FLASH IT

M5Stack Cardputer-ADV · ~30 g of filament · open source (MIT)

THREE STEPS TO A GROOVEBOX

1 · PRINT

THE SHELL

Grab the STLs and the keycap label sheet from MakerWorld. One evening on any FDM printer; the label top and keys use a multi-color plate.

MAKERWORLD →

2 · FLASH

THE FIRMWARE

Grab the pre-built .bin from GitHub Releases and flash it, or build from source — nothing beyond the Arduino IDE and one library.

GITHUB →

3 · JAM

THE FACTORY CARD

Copy the demo card to any microSD: a five-pattern arranged track plus a CC0 sample pack. Power on, hold LOAD, press PLAY.

DOWNLOAD EXTRAS ↓

SOUND ▶ WHAT'S INSIDE

SYNTH TRACKS3 × 303 SVF

VOICES1 MONO(303) → 3 POLY

OSCSAW SQR TRI SIN WT+8

DRUM LANES8 × 808/909/SMP

MIC SAMPLEHOLD AUX · 2.6 s

RESAMPLEHOLD SONG · 1.9 s

SEQUENCER8 PAT × 16 STEPS

SONG MODE64-SLOT CHAIN

ACCENT / SLIDEREAL 303 GRAMMAR

PROJECTS8 SLOTS → microSD

AUDIO22.05 kHz · ESP32-S3

KEYS1 KEY = 1 FUNCTION

FEATURES

The pattern grid: three synth rows above eight drum lanes

FOUR TRACKS, ONE GRID

Three synth rows sit directly above eight TR-style drum lanes — kick at the bottom, the whole arrangement on one screen.

The SOUND page with filter parameters and live oscilloscope

MONO 303 ↔ 3-VOICE POLY

Every synth track flips between a slide-and-accent mono voice and chord polyphony with one setting. Overlap notes: slide in mono, chord in poly.

Piano-layout keycaps with dead keys at the E–F and B–C gaps

THE KEYBOARD IS A PIANO

Whites on the home row, sharps above, and the E–F / B–C gaps deliberately dead. Your piano muscle memory just works.

Mic sampling with the footer as a live level meter

SAMPLES THE MIC

Hold one key, speak, release — auto-trimmed, written to SD, and playing on a drum lane before you've lowered the device.

RESAMPLES ITSELF

Bounce two seconds of the running mix onto any pad, clear the pattern, and build the next layer on top of the last one.

SONG MODE

Chain patterns into a 64-slot arrangement with a loop point. Pattern switches land on the bar, live or sequenced.

EVERY KEY, ONE FUNCTION

Microgroove v6 keymap — one key per function, hold for the orange second function — Orange marks the hold (0.5 s) function; green marks the sampling holds. The note keys are a real piano — whites on the home row, sharps above, the E–F and B–C gaps left dead. The printed keycap labels match this map exactly.

GET IT

Microgroove is free and open source. The firmware, shell files, factory sample pack, and full manual are one click away.

MAKERWORLD GITHUB

Built nights and weekends at lebiro.studio — if it earns a place on your desk, a coffee keeps the next feature coming.