24vled esp32c6

matter-led

A Matter-compatible 5-channel RGBCW LED controller built on a custom PCB with an ESP32-C6, written entirely in Rust. Pairs natively with Apple Home, Google Home, and any other Matter controller -- no proprietary hub required.

Hardware

Board

The controller is a 2-layer PCB designed in KiCad 9. It accepts 24 V DC input through a Molex 2601-1106 connector, protected by a 10 A mini blade fuse (Littelfuse 0297010.WXNV). A Recom R-78E5.0-1.0 switching regulator steps 24 V down to 5 V / 1 A to power the Waveshare ESP32-C6 module. Two 470 uF electrolytic capacitors (Panasonic EEUFR1V471L) filter the converter input.

Five AO3400A N-channel MOSFETs in SOT-23 packages switch the LED channels on the low side. Each gate is driven from a GPIO through a 100 ohm series resistor; 10 kohm pull-downs hold the gates low during boot. The MOSFETs switch the 24 V rail directly, so the LED strips see full supply voltage.

LED strip

The board drives 24 V RGBCCT LED strips with a common-anode, 6-pin configuration (V+, R, G, B, CW, WW). The target strip uses 5050-package RGB LEDs alongside 2835-package tunable-white LEDs, with a colour temperature range of 2000--6500 K and a CRI of 95. At 168 LEDs/m drawing 34.56 W/m, a 5 m reel pulls around 173 W. The strip is IP20 (no weatherproofing). Five independent PWM channels allow continuous colour temperature tuning between 2000 K and 6500 K, as well as full-gamut RGB colour mixing.

An example strip that matches these specs: https://www.aliexpress.com/item/1005006132338333.html

Power supply

Use a 24 V DC supply rated for the strip length you intend to drive. The board fuse is 10 A, so the practical ceiling is around 240 W at the input connector. A Mean Well LRS-350-24 or equivalent is a reasonable choice for a full 5 m strip.

GPIO mapping

Firmware

The firmware is a no_std Rust binary targeting riscv32imac-unknown-none-elf. It requires nightly Rust (minimum 1.88) for type_alias_impl_trait and the alloc error handler.

Architecture

The async runtime is Embassy. Hardware access goes through esp-hal, and the Matter protocol stack is rs-matter with the rs-matter-embassy integration layer. Networking uses smoltcp via embassy-net with DHCPv4 and IPv6 support. BLE commissioning is handled by trouble-host over the ESP32-C6's radio.

The device advertises as a Matter Extended Color Light (device type 0x10D) on endpoint 1, exposing the following clusters:

• OnOff -- power state with smooth 400 ms transitions.
• LevelControl -- brightness from 1 to 254 (Matter range).
• ColorControl -- hue/saturation mode and colour temperature in mireds (153--500, i.e. 6500 K down to 2000 K).
• Identify -- cycles through red, green, blue to visually locate the device.

A second endpoint (endpoint 2) exposes an On/Off Light Switch that acts as a "max brightness" override, driving all five channels at the current brightness level simultaneously.

PWM control

The LEDC peripheral is configured with a single 13-bit timer at 4882 Hz, giving 8192 discrete duty levels per channel. A dedicated async task runs at 50 Hz (20 ms per frame), interpolating between the current and target PWM state with a cubic ease-in-out curve. RGB transitions are mixed in Oklab colour space for perceptually uniform blending; CW/WW transitions use linear interpolation in Kelvin space (converted from mireds). All output values pass through gamma 2.2 correction before hitting the LEDC registers.

Colour temperature

The firmware maps the Matter mired range (153--500) to a mix ratio between the CW and WW channels. Conversion goes through Kelvin (K = 1,000,000 / mireds) and interpolates linearly in that space, which is more perceptually uniform than interpolating in mireds directly.

Memory layout

The ESP32-C6 has 8 MB of flash. The firmware reclaims bootloader RAM for heap use:

The KV store sits at offset 0x700000 and uses sequential-storage with 32 x 4 KB sectors.

Matter commissioning

The discriminator is derived from the last 12 bits of the device MAC address, giving each board a unique but deterministic identity. The default passcode is 20202021 (the Matter test value). Pairing data is printed to the defmt log on boot.

To commission, use any Matter controller and enter the discriminator and passcode, or generate a QR code with vendor ID 0xFFF1 and product ID 0x8000.

Factory reset

Hold the BOOT button (GPIO 9) during power-on. The firmware erases the 128 KB flash KV store and reboots after a 2-second delay. All Matter fabrics, ACLs, and saved state are wiped.

Building

Prerequisites

Install the toolchain via mise:

mise install

This sets up nightly Rust with the riscv32imac-unknown-none-elf target and the espflash tool.

Alternatively, install manually:

rustup toolchain install nightly
rustup target add riscv32imac-unknown-none-elf
cargo install espflash

Compile and flash

cd firmware
cargo build --release
cargo espflash flash --release --monitor

The --monitor flag opens a serial console after flashing so you can see defmt log output including the pairing discriminator.

Hardware CI with KiBot

A GitHub Actions workflow runs KiBot on every push or PR that touches schematic, PCB, or KiBot configuration files. It uses the ghcr.io/inti-cmnb/kicad9_auto_full container image and runs ERC/DRC preflight checks before generating outputs.

Generated artifacts

All outputs land in hardware/output/ and are uploaded as build artifacts.

The BOM is split by sourcing. Components with an LCSC field go into the JLC BOM for PCBA ordering; everything else (the ESP32-C6 module, Recom regulator, fuse, connectors) goes into a separate BOM formatted for Mouser/Digikey with MPN grouping. A third BOM variant is formatted for Octopart one-click import -- upload the CSV and Octopart resolves MPNs across distributors, shows stock and pricing, and lets you build a cart in one step.

Bill of materials

On-board components

Off-board (not on PCB)

The KiBot CI generates three BOM formats automatically: a JLC-formatted CSV for LCSC parts (ready for JLCPCB PCBA upload), a Mouser/Digikey BOM grouped by MPN for manual ordering, and an Octopart CSV for one-click quoting across distributors. All three are available as build artifacts under hardware/output/bom/.

Project structure

.
├── firmware/           Rust firmware for the ESP32-C6
│   ├── src/bin/        Entry point (main.rs)
│   ├── src/clusters/   Matter cluster handlers (OnOff, LevelControl, ColorControl, Identify)
│   ├── src/led/        PWM control, colour conversion, device state
│   └── tests/          On-target embedded tests
├── hardware/           KiCad 9 schematic and PCB
│   ├── external/       Third-party symbol libraries
│   └── internal/       Custom symbols (Waveshare module)
├── crates/
│   └── sticky-signal/  Async signal primitive (no_std, multi-waiter)
├── config.kibot.yaml   KiBot output definitions
└── .github/workflows/  CI for hardware artifact generation

License

See individual crate and hardware directories for licensing details.