Off‑the‑shelf — the Pimoroni Pico Scroll Pack (a 17×7 white LED matrix + 4 buttons) on a plain Raspberry Pi Pico. The matrix is the editor's lane × step pad grid in miniature: rows are lanes, columns are steps, brightness is accent / normal / ghost. Edit on the web with Live sync; the device mirrors play/stop/tempo/track both ways.
PM_G‑1 Grid
RP2040 · 17×7
Four buttons: A = play/stop (hold = cycle view: Grid → Pendulum → BPM);
B = next track (hold = next set list); X / Y = tempo −/+ (hold to repeat, ±5 after ~1.5 s).
Keyboard: A / B / X / Y, space = play, V = cycle view.
PM_G‑1 Grid