/*@BUILD:include:src/header.html@*/

# PM_D‑1 Display

A display‑piece metronome — the pendulum is an RGB light bar that combines every lane's subdivisions & accents; a printed tempo scale with a sliding weight sets the tempo.

/*@BUILD:include:src/infoembed.html@*/

## What it is

Hardware Display piece~$41 one‑off

A metronome as an object: the silhouette of a classic pyramid wind‑up unit, but the swinging pendulum is pure RGB light. The whole bar is the display — every lane's subdivisions & accents ride along its length as moving points of light (all meters combined), a printed tempo scale runs up the vertical axis, and a sliding weight sets the tempo just like the mechanical original.

It's a beautiful, glanceable tempo reference for the shelf, the studio, or a shop window: accents glow amber, normal steps cyan, ghosts soft violet, and the pendulum eases to each beat exactly as a weighted rod would. It runs the same grooves as everything else (load any program string), plays the click through a small speaker, and is powered over USB‑C with a second "thru" port to daisy‑chain. There's no power switch — the real unit starts when you lift it from its holder / set it swinging. No instrument I/O; it's a showpiece.

Dimensions & profile — ≈ 4.7 × 7.1 × 3.1 in (120 × 180 × 80 mm), a truncated‑pyramid plinth

↕ 7.1 in (180 mm)
Front
RGB‑light pendulum bar + tempo scale
↔ 4.7 in (120 mm) base
↕ 7.1 in (180 mm)
Side
USB‑C in base
↔ 3.1 in (80 mm) deep
Spec & bill of materials

Rough parts list — a USB‑C‑powered RP2040 display piece driving addressable RGB light. Ballpark one‑off prices (USD); cheaper at volume.

Part | Qty | ~$
--- | --- | ---
Brain
RP2040 board, USB‑C — e.g. Waveshare RP2040‑Zero | 1 | 4
RGB light
Addressable RGB LEDs (WS2812B) — a strip down the pendulum bar, ~40 px | 1 | 5
Frosted acrylic diffuser / light‑guide — the glowing pendulum bar | 1 | 3
Audio
MAX98357A I²S amp + small speaker — the click | 1 | 4
Power & build
2× USB‑C (data+power & power‑thru) + PWR LED — daisy‑chain | 1 | 3
Tilt / lift sensor (accelerometer) — starts when lifted from its holder | 1 | 2
Custom PCB (or perfboard) | 1 | 4
Passives, wire | — | 2
Pyramid enclosure — cast/CNC aluminium or hardwood, frosted front panel | 1 | 14
Total (one‑off) |  | ≈ $41

Embed this widget elsewhere with one `<div>` + a script — see the embed docs.

/*@BUILD:include:src/footer.html@*/