LED Badge (ESP32‑C3 + 10×10 Addressable Matrix)

A hackable, battery‑powered LED badge built with Atopile for hardware and PlatformIO/Arduino for firmware. It features a 10×10 SK6805 LED matrix, an ESP32‑C3 module, USB‑C power/data, on‑board charging and regulation, a 6‑axis IMU, an I²S microphone, and a user button. Press the button to cycle through multiple visual/audio‑reactive modes.

Highlights

• MCU: ESP32-C3-MINI-1
• LEDs: SK6805-EC20 10×10 addressable matrix (100 pixels)
• Power: USB‑C, BQ25185 Li‑ion charger + power path, TPS63020 3V3 buck‑boost
• Sensors: LSM6DS3 IMU (accel + gyro), ICS‑43434 I²S microphone
• I/O: 1x user button, USB‑CDC serial console at 115200 baud

Repository layout

• led_badge.ato — Hardware design (Ato/Atopile)
• ato.yaml — Build targets and package dependencies
• layouts/ — Generated KiCad projects for different form factors
  • badge/ (full badge), grid100x100/, strip10/, esp32_minimal/
• parts/ — Atomic parts (symbols/footprints/STEP)
• firmware/ — PlatformIO project (Arduino framework)

Hardware architecture (Ato)

The badge is defined in LED_BADGE and uses Atopile packages from the registry:

• ESP32‑C3 module, USB‑C connector
• BQ25185 charger → battery → system power → TPS63020 buck‑boost → 3V3 rail
• 10×10 SK6805 matrix, LSM6DS3 IMU over I²C, ICS‑43434 microphone over I²S

Build targets (from ato.yaml):

• badge → led_badge.ato:LED_BADGE
• grid100x100 → led_badge.ato:SK6805EC20_grid100x100
• strip10 → led_badge.ato:SK6805EC20_strip10

Building the PCB

• Open the generated KiCad project at layouts/badge/badge.kicad_pro to view/modify the PCB.
• To regenerate from Ato sources, use the Atopile extension (Cursor/VS Code) and run the build for the badge target. This will refresh the KiCad files under layouts/.

Firmware (PlatformIO/Arduino)

The firmware lives in firmware/. It targets esp32-c3-devkitm-1 and uses:

• Adafruit NeoPixel (LEDs)
• Adafruit LSM6DS + Adafruit AHRS (IMU fusion)
• arduinoFFT (audio spectral analysis)

Quick start:

1. Install the PlatformIO extension for VS Code (or pipx install platformio).
2. Open the firmware/ folder as a PlatformIO project.
3. Connect the badge over USB‑C.
4. Build and upload to the esp32-c3-devkitm-1 environment.

CLI equivalents:

cd firmware
pio run                      # build
pio run -t upload            # flash
pio device monitor -b 115200 # serial console

Pin map (logical)

• LED data: GPIO8
• Button: GPIO9 (INPUT_PULLUP; press = LOW)
• I²C: SDA GPIO5, SCL GPIO6
• I²S mic (ICS‑43434): SCK/BCK GPIO0, WS/LRCLK GPIO3, SD GPIO1

Run modes (press button to cycle)

• Rainbow: ambient dissolve across the matrix
• Ball: physics‑like ball steered by tilt (IMU)
• Life: Conway’s Game of Life with age‑based coloring
• Sweep: moving highlight across pixels
• Center: static center block
• Multi‑ball: 3 bouncing balls
• Level: electronic bubble level using IMU gravity vector
• Nyan: placeholder for simple 4‑frame animation
• Spectrogram: scrolling FFT spectrogram from the I²S mic
• Vertical line: left‑edge test pattern
• Audio levels: 10‑band logarithmic histogram
• Beat flash: bass‑beat detection flashes the matrix

Tip: open the serial monitor at 115200 to see I²C scan results, mic/FFT debug, and mode logs.

Flashing notes (ESP32‑C3)

• If auto‑upload fails, hold the module’s BOOT button, tap RESET, then release BOOT to enter download mode and retry.
• USB‑CDC is enabled by default; the serial port appears without external UART hardware.

Customizing

• LED matrix size and chaining are defined in led_badge.ato (SK6805EC20_grid100x100 and SK6805EC20_strip10).
• Power rail limits (USB 5V, charger currents, 3V3 regulation) are constrained in LED_BADGE and can be adjusted as needed.

License

This project is provided under the terms in LICENSE.txt.

Credits

• Hardware is defined in Ato using packages from the Atopile registry.
• Firmware builds on libraries from Adafruit and the Arduino ecosystem.