PM_K‑1 Kit

Build it yourself: a Raspberry Pi Pico on the 52Pi breadboard kit becomes a touchscreen polymeter metronome — same engine, same program strings, with MicroPython firmware you flash in two minutes.

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What it is

Buildable nowRaspberry Pi Pico52Pi EP‑0172 kit~$45 incl. Pico

This is the first member of the family you can actually build today from off‑the‑shelf parts: a Raspberry Pi Pico seated on the 52Pi EP‑0172 "Pico Breadboard Kit Plus", which carries a 3.5″ ST7796 320×480 capacitive‑touch screen (GT911), a PSP joystick, a WS2812 RGB LED, a buzzer and two buttons — all pre‑wired, so you don't solder anything; you just seat the Pico and copy one file onto it.

It runs the same polymeter engine and the same program strings as the web editor: design a groove on the site, copy its program string into the firmware's PROGRAMS list, and it plays on the device. Tap the screen, nudge tempo with the joystick; the RGB flashes each beat (amber accent / cyan normal / violet ghost) and the buzzer clicks. Powered over the Pico's USB.

Wiring — the EP‑0172 fixed pinout (Raspberry Pi Pico)

Everything is wired on the board; this is just what the firmware drives. No breadboarding required.

Component	Raspberry Pi Pico pins
Display — 3.5″ ST7796, 320×480 (SPI0)
SCK / MOSI	GP2 / GP3
CS / DC / RST	GP5 / GP6 / GP7
Touch — GT911 capacitive (I2C0)
SDA / SCL — addr 0x5D	GP8 / GP9
Controls & feedback
PSP joystick X / Y	ADC0 (GP26) / ADC1 (GP27)
Button A (play/stop) / Button B (tap)	GP15 / GP14
WS2812 RGB LED	GP12
Buzzer	GP13

Parts

An off‑the‑shelf kit, not a custom board — ballpark one‑off prices (USD).

Part	Qty	~$
Raspberry Pi Pico (or Pico W / Pico 2) — the brain	1	5
52Pi EP‑0172 "Pico Breadboard Kit Plus" — 3.5″ ST7796 cap‑touch, GT911, PSP joystick, WS2812 RGB, buzzer, 2 buttons, breadboard, acrylic panel	1	38
USB cable — power + flashing	1	2
Total (one‑off)		≈ $45

Reference: 52Pi EP‑0172 wiki · vendor code. Lots may ship the screen as ST7796 (320×480) — this build targets that.

Firmware — flash it in two minutes

Download main.py ↓ Source + README ↗

Two separate steps — and main.py is not a drag‑and‑drop file. The RPI‑RP2 drive only accepts a .uf2 firmware file; a .py copied there is discarded on reboot. You drag‑and‑drop the firmware once, then copy main.py over USB serial.

Install MicroPython (drag‑and‑drop, one time): hold BOOTSEL, plug the Pico into USB, and drop the MicroPython .uf2 onto the RPI‑RP2 drive (Pico / Pico 2). It reboots on its own and the drive disappears — that's correct.
Copy main.py (the Pico is no longer a USB drive, so use a serial tool): in Thonny pick the interpreter MicroPython (Raspberry Pi Pico), then File ▸ Save as ▸ Raspberry Pi Pico as main.py; or mpremote cp main.py :main.py.
Reset — it boots straight into the metronome.
Add your own grooves by pasting program strings from the editor into the PROGRAMS list at the top of main.py. If colours, touch, or the joystick look off, flip a flag in the CONFIG block (see the README's calibration notes).

It's one self‑contained file — the ST7796 driver, GT911 touch, WS2812 RGB, buzzer and the polymeter engine, no external libraries.

CircuitPython edition — USB drive + editor (experimental)

An alternative firmware that makes the Pico mount as a USB drive carrying the firmware, your tracks (programs.json) and a copy of this editor — design grooves on the web and write them straight to the device, no Thonny. A full lanes/pads display with anti‑aliased text drives the touchscreen. The MicroPython firmware above stays the simple, rock‑solid option. (USB‑MIDI audio out to your computer's speakers is the next step.)

Download CircuitPython bundle ↓ Source + README ↗

Flash CircuitPython (raspberry_pi_pico) via BOOTSEL → the CIRCUITPY drive appears.
Unzip the bundle onto CIRCUITPY (it's a normal drive — just drag everything on). It runs on boot.
Reprogram it from the web: build a set list in the editor, then the set‑list ⋯ menu → 📟 Save to device → pick the CIRCUITPY drive. The Pico auto‑reloads with your grooves. (In Chrome/Edge it writes straight to the drive; otherwise it downloads programs.json to drag on.) 📥 Load from device reads it back.

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