XIAO Drone LED Controller

Firmware for a Seeed XIAO ESP32-C3 that drives a WS2812 LED strip on an FPV drone. Written in Rust (no_std), running on the Embassy async runtime.

Features

• WS2812 LED strip driven via SPI+DMA (ws2812-spi) on GPIO10 (200 LEDs, configurable)
• Modular pattern engine — Pattern trait with swappable implementations
  • RippleEffect (default) — expanding ring particles with random hues on a deep navy background
  • RainbowCycle — classic hue-shifting rainbow
• Current-limited brightness — estimates strip draw (8 mA/channel model) and clamps brightness to a configurable mA budget (default 2000 mA)
• Wi-Fi access point — open AP (XIAO-LED-Controller) with DHCP server and interactive web UI
• BLE support — via bleps (not yet wired up)

Hardware

• Seeed XIAO ESP32-C3
• WS2812B LED strip on GPIO10 (SPI2 MOSI)
• USB power (2A budget)

Building

Requires a Rust nightly toolchain with the riscv32imc-unknown-none-elf target.

cargo build

Flashing

Flash with probe-rs:

cargo run

HTTP API

Connect to the XIAO-LED-Controller Wi-Fi network and open http://192.168.4.1 in a browser for the interactive control page.

GET /

Returns the control page with brightness and LED count sliders. Slider changes are sent to the device in real time.

GET /set

Updates LED parameters via query string. Returns 204 No Content.

Parameter	Type	Range	Description
brightness	int	0–255	Global brightness level
num_leds	int	1–200	Number of active LEDs driven
fps	int	1–150	Animation frame rate

Both parameters are optional and can be combined.

Examples:

GET /set?brightness=128
GET /set?num_leds=60
GET /set?brightness=200&num_leds=100
GET /set?fps=30

Project Structure

src/
  bin/main.rs   — entry point, task spawning, LED/Wi-Fi/DHCP/HTTP tasks
  lib.rs        — crate root
  pattern.rs    — Pattern trait and LED pattern implementations
  state.rs      — shared LedState (brightness, num_leds, fps, flight mode) via async mutex

License

Unlicensed / private project.