A 16-track MIDI step sequencer for the M-Vave SMC-PAD, in the spirit of the Digitakt and the BeatStep Pro: step and live recording, per-step velocity, micro-timing, probability and conditions, ratchets, parameter locks, euclidean patterns, 16 patterns with chains, note repeat that follows how hard you press, MIDI clock in and out, and an Ableton Live companion that paints the pads with your Drum Rack.
It runs on the SMC-PAD with the open firmware (our bootloader plus the Arduino core); it is an Arduino sketch, so you can read it, change it and upload your own version.
Everything below — every animation included — comes from the real firmware: the pictures are
made by running this sketch in the SMC-PAD emulator
(tools/make_images.py).
- Install
- Your first beat
- The four modes
- PLAY mode · STEP mode · Live recording · MUTE mode · PATTERN mode
- Tempo and sync · Ableton Live · Bluetooth
- Reference: buttons · knobs · MIDI
- Building, the emulator, design notes
You need an SMC-PAD running the open firmware's bootloader — see open-smc-pad (it installs from the stock firmware over USB, no tools inside the case).
- Ready-made: download
GrooveBox.binfrom the releases and send it to the pad:dfu-util -d 1209:0002 -a 0 -D GrooveBox.bin(hold SHIFT + PLAY while switching the pad on to get the bootloader, or upload from a running firmware). - From the Arduino IDE / arduino-cli: add
https://github.com/fedepaj/open-smc-pad/releases/latest/download/package_smcpad_index.jsonto Settings → Additional boards manager URLs, install SMC-PAD (open firmware) from the Boards Manager (details), openGrooveBox/GrooveBox.ino, board M-Vave SMC-PAD (open firmware), Upload.
The pad shows up as a class-compliant USB-MIDI device ("SMC-PAD open fw") and, once Bluetooth is on, as a BLE-MIDI one. Out of the box the 16 tracks play notes 36–51 on channel 10: a General MIDI / Drum Rack kit.
- Press PAD BANK: STEP mode. The pads are now the 16 steps of the selected track (track 1, the kick). Step 1 is top-left, reading like a page.
- Tap steps 1, 5, 9, 13.
- SHIFT + pad 3 selects track 3 (the snare): tap steps 5 and 13.
- PLAY. The white light walking over the pads is the playhead. Tap a lit step to turn it off.
- PAD BANK again: back to PLAY mode, where every pad is a track and flashes when it plays.
Your work is saved by itself (a few seconds after you stop, and at every pattern change).
The colours always tell where you are; the PAD BANK and KNOB BANK LEDs too.
 PLAY (default) — the pads are the 16 tracks |
 STEP — PAD BANK — the steps of the selected track |
 MUTE — SHIFT + PAD BANK — tap to mute a track |
 PATTERN — SHIFT + KNOB BANK — the 16 patterns |
Pressing the same combination again goes back to PLAY. Everywhere, SHIFT + a pad selects that track (in PLAY mode, hitting a pad selects it too).
Each pad plays its track's note with the velocity of your hit. Holding a pad sends polyphonic aftertouch from how hard you press.
SHIFT + pads 9–16 (as on the stock firmware):
| pad | |
|---|---|
| 9 / 10 / 11 / 12 | velocity curve: linear / soft / hard / always full |
| 13 / 14 | transpose −1 / +1 semitone (what you play live) |
| 15 / 16 | octave −1 / +1 · 15 + 16 together: back to normal |
Hold NOTE REPEAT and a pad (in either order): the pad repeats in time with the sequencer. Press harder for louder repeats — the velocity follows the pressure, MPC style. While recording, the repeats are recorded too: instant hi-hat rolls.
- NOTE REPEAT + knobs 1–4: rate, swing, tempo, latch.
- SHIFT + NOTE REPEAT: the settings on the pads — pads 1–8 rate (1/4, 1/4T, 1/8, 1/8T, 1/16, 1/16T, 1/32, 1/32T), 9–13 swing (off, 1–4), 14 latch, 15 MIDI clock (out / in / off, see Tempo and sync), 16 tap tempo (it blinks in time). NOTE REPEAT closes the page.
- With latch on, NOTE REPEAT toggles, and pads keep repeating after you let go; hit a pad again to stop it.
Each pad is a step of the selected track; < > go through its pages (tracks can be up to 64 steps: four pages). Step 1 of a page is top-left. Dark steps are off; the faint ones mark the beats.
Tap an off step to turn it on (with the velocity of your tap), tap a lit one to turn it off. Hold steps and turn knobs to edit them (several held steps change together):
| knob | with a step held |
|---|---|
| 1 | velocity |
| 2 | micro-timing: −11 … +11 / 24 of a step |
| 3 | how often it plays: probability 100 % … 1 %, then 1:2 2:2 1:3 2:3 3:3 1:4 2:4 3:4 4:4 (play on the n-th of every m loops), FILL, NOT FILL |
| 4 | ratchet: 1–4 hits inside the step |
| 5–8 | parameter locks: the value of the track's lock CCs (CC 70–73 by default) on this step only; turn left past 0 to remove |
While a knob turns, the pads show its value (a bar, or the choice among a few), then the steps come back. Steps with a lock are lighter; steps with a condition pulse.
FILL: outside PLAY mode, holding NOTE REPEAT is the fill button: steps set to FILL play only then, NOT FILL ones only otherwise.
In STEP mode (no step held), knob 7 spreads that many hits evenly over the track and knob 8 rotates them — the classic euclidean rhythms (3 in 8, 5 in 16 …). It rewrites the track's steps.
Press REC (it blinks), then PLAY, and play the pads in PLAY mode: each hit lands on the nearest step of its track, keeping how early or late you were as micro-timing. Turning knobs 1–4 of page B records parameter locks on the step that is playing (if it is on). REC again stops recording.
SHIFT + REC (hold 1 s) clears the selected track.
SHIFT + PAD BANK. One pad per track: tap to mute, tap again to bring it back. Playing tracks flash.
SHIFT + KNOB BANK. 16 patterns: green is playing, blue holds something, dark is empty.
- Tap a pattern: it takes over at the end of the current one (at once when stopped).
- Hold one and tap others: a chain, played in that order, looping.
- SHIFT + a pad: copy the current pattern there.
- SHIFT + knob 3: the pattern length (16, 32, 48, 64 steps) — when a queued pattern takes over. Tracks can be shorter or longer and loop on their own (polymeters).
Patterns live in the pad's flash and survive power-off and firmware updates.
- SHIFT + knob 1: tempo (30–300 BPM); SHIFT + knob 2: swing of the pattern.
- Tap tempo: SHIFT + NOTE REPEAT, then tap pad 16.
- MIDI clock: SHIFT + NOTE REPEAT, pad 15 steps through three modes (kept across power
cycles):
- OUT (blue, the default): the pad is the master. It sends MIDI clock (also when stopped, so followers know the tempo) and start / stop with PLAY / STOP.
- IN (green while a clock comes in, orange while none does): the pad follows another clock (Ableton, a drum machine) and starts, stops and keeps time with it. It sends no clock.
- OFF (dim): the pad's own tempo; it sends no clock and ignores incoming clock. For Bluetooth to a host that does not sync, or a setup with another master.
The ableton/SMC_PAD control surface script makes the pad part of Live:
- the pads take the colours of your Drum Rack, and empty Drum Rack pads stay dark;
- with the pad following Live's clock, the pad's PLAY / STOP start and stop Live.
Setup:
tools/install_ableton.sh(copies the script to your User Library's Remote Scripts), then restart Live.- Settings → Link, Tempo & MIDI → Control Surface: SMC_PAD, input and output SMC-PAD open fw.
- MIDI ports, SMC-PAD open fw:
- Live leads (recommended: Live's clock is steadiest): output Sync on, input Sync off; on the pad, SHIFT + NOTE REPEAT → pad 15 to IN (green).
- The pad leads: input Sync on, output Sync off, pad 15 on OUT (blue); Live follows PLAY on the pad.
- Input Track on, so the notes reach your tracks.
- Select a track with a Drum Rack. The pads follow the selected (or armed) track's rack.
The tracks are matched by note: track 1 plays note 36 = the Drum Rack's first pad, and so on.
Hold BT for a second: Bluetooth on or off (the LED blinks while waiting, stays lit when connected). The pad is then a BLE-MIDI device too — macOS (Audio MIDI Setup → Bluetooth), iOS and Android apps (GarageBand, Koala, FL Studio …) connect to it; it sends the same notes, clock and messages as over USB.
| button | with SHIFT | |
|---|---|---|
| BT | hold: Bluetooth on / off | |
| PAD BANK | STEP ↔ PLAY | MUTE mode |
| KNOB BANK | knob page A ↔ B | PATTERN mode |
| < > | STEP: page · elsewhere: previous / next track | |
| PLAY | start / stop (Live's, when synced to it) | |
| STOP | stop (again: all notes off) | hold 1 s: kit back to notes 36–51, channel 10 |
| REC | live recording on / off | hold 1 s: clear the selected track |
| SHIFT | the second layer | |
| NOTE REPEAT | PLAY: note repeat · elsewhere: fill | note repeat settings |
< and > blinking together: low battery.
| knob | page A (KNOB BANK off) | page B (KNOB BANK on) | with SHIFT |
|---|---|---|---|
| 1 | track velocity (new steps) | CC 70 → lock 1 | tempo |
| 2 | gate (note length) | CC 71 → lock 2 | pattern swing |
| 3 | track length (1–64) | CC 72 → lock 3 | pattern length |
| 4 | track speed (½×, 1×, 2×) | CC 73 → lock 4 | track note |
| 5 | — | CC 74 | track MIDI channel |
| 6 | — | CC 75 | |
| 7 | euclidean hits | CC 76 | |
| 8 | euclidean rotation | CC 77 |
Page B sends on the selected track's channel; knobs 1–4 there are the track's lockable CCs, and their position is the value locked steps return to. With steps held in STEP mode the knobs edit the steps instead (STEP mode).
| notes | one per track (default 36–51), channel per track (default 10); note on/off with velocity, gate length |
| aftertouch | polyphonic, from pad pressure (PLAY mode) |
| CC | 70–77 from knob page B; 70–73 also from parameter locks |
| clock | 24 PPQN; out in clock mode OUT (the default), followed in mode IN, neither in OFF |
| transport | out: Start / Stop (mode OUT); in: Start, Continue, Stop (mode IN) |
| SysEx | F0 7D 53 50 … — the Ableton script's Drum Rack picture, hello and transport (protocol) |
Over USB and BLE-MIDI at once. (The 3.5 mm MIDI OUT is not driven yet.)
GrooveBox/is a plain Arduino sketch:arduino-cli compile --fqbn smcpad:br25:smcpad GrooveBox.Model.hthe data,Engine.hthe sequencer (96 PPQN clock, event queue),Store.hthe pattern storage,GrooveBox.inothe interface.- The emulator runs it on your computer: with open-smc-pad cloned
next to this repository,
../open-smc-pad/arduino/sim/build.sh GrooveBox(see its README);tools/make_images.pyrebuilds every picture of this page from the firmware. - Why it is built this way — modes, storage, timing — is in docs/design.md.
MIT — see LICENSE. Not affiliated with M-Vave.