Unified pcb

motionhexa

PCB designs and code for a motion-reactive, battery-powered hexagonal glowy object.

What is it?

It's a hexagon. Colors swirl & shift as you move it. Pixels fall towards the earth. The triangle stays put. USB-C Rechargable.

Controls

There is a button on that back of an assembled hexa that you can press by squeezing through the front and back of the case for a single click.

• Single click: Next Pattern
• Double click: Previous Pattern
• Long (1-second) squeeze: Power on and off
• Very long (10-second) squeeze: Soft reset

Hardware

v8

• RP2354 dual-core ARM processor
• BMI270 motion sensor
• LMD4030 PDM microphone
• BQ27427 battery monitor
• SK9822-EC20 pixels
• LY4176D lipo charger

v5-v6

• RP2040 dual-core ARM processor
• ICM-20948 motion sensor
• LMD4030 PDM microphone
• BQ27421 battery monitor
• SK9822-EC20 pixels
• LP28013HQVF lipo charger

Project layout

• hexacontroller/ contains the pcb for the logic, power, and motion circuitry.
• hexa/ contains the pcb for the hexagonal lattice of 271 SK9822-EC20 pixels wired in zig-zag order
• src/ all project-specific source
• lib/ submodule dependencies dustlib and BQ27427 Battery Fuel Gauge

The project is built using PlatformIO in Visual Studio Code.

Building

You will likely need to run

git submodule update --init

in the source after git clone in order to fetch the submodules for building.

Build environment

The PlatformIO project has a number of build environments:

• v5 - MakerFaire 2025 hardware
• v6 - online orders 2025-Sept 2026
• v8 - MakerFaire 2026 hardware and subsequent online orders

Libraries & Dependencies

PlatformIO should fetch the apprpriate version of each dependency on first build.

• FastLED - A library for fast 8-bit math and rendering colors onto pixels
• SparkFun_ICM-20948 - A library for interfacing with the ICM-20948 Motion sensor
• edrean/BQ27427 Battery Fuel Gauge - A library for interfacing with the BQ27421 (very similar to BQ27427) battery monitor (PlatformIO should build against my BQ27427 Battery Fuel Gauge fork)
• dustlib, my work-in-progress pixel library

How to write patterns

Please be aware that modifying the code is at your own risk

Pattern code is in src/patterns.h

You can write your own new pattern by subclassing Pattern.

class MyAwesomePatternIdea : public Pattern {
public:
  MyAwesomePatternIdea() { }
  void update() {
    // Example 1: Show a rainbow down the zig-zag pixel wiring of the hexa
    for (int px = 0; px < ctx.leds.size(); ++px) {
      CRGB color = CHSV(10 * px - millis()/10, 0xFF, 0xFF);
      ctx.leds[px] = color;
    }

    // Example 2: Show a rainbow pulsing outwards from the center using axial coordinates
    /*
    Axial centerAxial = axial.axialFromPixelIndex(ctx.leds.size()/2);
    for (int px = 0; px < ctx.leds.size(); ++px) {
      Axial ax = axial.axialFromPixelIndex(px);
      // the sum of the differences of q,r,s gives us the "cube distance" which in 2d is shaped like a hexagon
      int distanceToCenter = abs(ax.q() - centerAxial.q()) + abs(ax.r() - centerAxial.r()) + abs(ax.s() - centerAxial.s());
      CRGB color = CHSV(20 * distanceToCenter - millis()/5, 0xFF, 0xFF);
      ctx.leds[px] = color;
    }
    */

    // Example 3: Show a small hexagon that moves around are you tilt the hexa
    /*

Each pattern needs to be added to the pattern list in main.cpp here. in order to run. You can add your own pattern by adding a line to the list where you find patternManager.registerPattern.

void setup() {
  # ...
  patternManager.registerPattern<MyAwesomePatternIdea>();
  # ...
}

This list defines the order that patterns run when you click the button.

USBBOOT (help my hexa won't boot)

If your hexagon stops doing hexagon things while you are hacking on it, does not respond to power cycle, and you are unable to re-flash it, you can put it into DFU mode using rp2040 USBBOOT.

• Carefully open the case using a flat, blunt tool, avoiding poking the battery.

• There is a button on the hexacontroller here:

• 

• Press and hold the button while plugging into a computer-attached usb port. You should see a drive (USB Mass Storage Device) appear called "RPI-RP2".

• You can now either re-flash the hexa yourself using PlatformIO or another tool OR

• Copy the stable binary hexa image from here onto the drive, and after the copy it should automatically reboot.

MotionHexagon