Same firmware as the idealized unit — only the panel hardware differs. Paste a patch
(e.g. v1;t120;kick:4;snare:4=.X.X;hatClosed:4/2), a set‑list code, or a
#p=…/#sl=… link.
Rough parts list for the device above — an RP2040 build with analog click injection. Ballpark one-off prices (USD); cheaper at volume.
| Part | Qty | ~$ |
|---|---|---|
| Brain & display | ||
| RP2040 board, USB‑C — e.g. Waveshare RP2040‑Zero / Pico‑clone | 1 | 4 |
| 2.0″ 320×240 IPS TFT, ST7789 — SPI | 1 | 8 |
| Controls | ||
| Arcade pushbutton, 24 mm — Prev · Next · Tap | 3 | 4 |
| Arcade pushbutton, 30 mm — Play | 1 | 2 |
| EC11 rotary encoder + knurled knob — tempo | 1 | 2 |
| Audio — analog click injection | ||
| PCM5102A I²S DAC — line‑level click | 1 | 3 |
| Dual op‑amp, NE5532 / OPA2134 — hi‑Z instrument buffer + summing mixer | 1 | 1 |
| Balanced line driver, DRV134 — (or cross‑coupled op‑amp) → 1/4″ TRS out | 1 | 4 |
| PAM8302A mono Class‑D + 8 Ω 2 W speaker — monitor | 1 | 4 |
| Connectors & power | ||
| 1/4″ jack — Inst In (TS) · Out (TRS) · Trig In (TS) | 3 | 3 |
| LiPo 1200 mAh + TP4056 charger + 5 V boost | 1 | 6 |
| Power slide switch + PWR LED | 1 | 1 |
| Build | ||
| Custom PCB (or perfboard) | 1 | 5 |
| Passives, headers, wire — R/C for the analog stage + decoupling | — | 3 |
| 3D‑printed enclosure + screws / standoffs | 1 | 5 |
| Total (one‑off) | ≈ $55 | |
Audio is summed in the analog domain: the DAC's click is mixed with a high‑impedance buffer of the 1/4″ instrument input, then fed to the balanced line driver (1/4″ TRS out) and the monitor amp — so your instrument is never re‑digitised (no added latency).