PM‑1 — Teacher
The full‑feature desktop console: a colour readout of every lane, fast set‑list navigation, and your instrument running straight through with the click mixed in — the hands‑on unit for a studio desk or a teaching room, on a non‑reflective matte‑black case. (A hands‑free, foot‑operated Stage stompbox is in the works for live use.)
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Designed for
The studio desk and the teaching room. Top‑mounted 1/4″ jacks keep cabling tidy; you plug your instrument in, the metronome click is summed into the signal in the analog domain (no re‑digitising, no added latency) and sent to a balanced 1/4″ TRS output for the desk or interface, plus a small monitor speaker. Powered over USB‑C — a wall adapter, or a power bank. The colour TFT shows tempo, the item name, and all lane patterns; arcade buttons + a recessed thumb‑roller make it quick to drive while you teach or track.
Bill of materials
Rough parts list — a desk/studio RP2040 build (USB‑C powered) 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 |
| Detented encoder (EC11 / PEC12) + side‑mount thumb‑roller — recessed; nothing to snap off | 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 |
| USB‑C bus power (5 V) + PWR LED — wall adapter or power bank; same port carries config; no battery | 1 | 1 |
| Build | ||
| Custom PCB (or perfboard) | 1 | 5 |
| Passives, headers, wire — R/C for the analog stage + decoupling | — | 3 |
| Die‑cast aluminium enclosure (Hammond 1590‑style) — bead‑blasted, matte‑black Type II anodise, laser‑etched legends | 1 | 12 |
| Total (one‑off) | ≈ $56 | |
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).