LEDController

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LightController

ESP32-C3 Super Mini based LED controller with USB-C PD input, DC barrel jack/ terminal block input, two PWM-dimmed LED strip channels, and an addressable NeoPixel output. Apple HomeKit native via HomeSpan, with optional MQTT status reporting.

Built as a one-person project for Year 1 Period 4 — Power up Yourself at Hanze University of Applied Sciences, Groningen.

Hardware

Custom PCB designed in KiCad (design files in pcb/).

Key Components

Power Input (Up to 24V tolorance)

• USB-C PD via CH224K — negotiates 5V/9V/12V/15V/20V from a PD source
• DC barrel jack — direct input (e.g. 12/24V wall adapter), bypasses PD negotiation
• Terminal Block — direct input if user have PSU input, bypasses PD negotiation.

Three inputs feed the LED strips directly and the AP63205 buck for 5V MCU power.

Outputs (All shares same power rail)

• Channel A — PWM-dimmed LED strip (low-side MOSFET, enable gate)
• Channel B — PWM-dimmed LED strip (low-side MOSFET, enable gate)
• NeoPixel — addressable RGB string via level-shifted DIN (SN74LVC1T45)

PCB History

The PCB was originally designed by Andrei (ihoneypot) as a basic LED controller. I modified the design to add:

• USB-C PD input with CH224K voltage negotiation
• DC barrel jack input as alternative power source
• ESP8266 → ESP32-C3 Super Mini swap (HomeKit-capable, smaller footprint)
• Unified power routing: three input paths merged to one rail, split to two LED strip outputs + NeoPixel output
• 3.3V→5V level shifter for NeoPixel data line

PD Status — Not Working

The CH224K PD negotiation circuit is currently disabled (ENABLE_PD 0 in config). During bringup we burned several CH224K chips and discovered through debugging:

• The 1kΩ resistor from VBUS to VDD acts as a voltage divider but the 0805 package cannot dissipate the power at higher voltages (P = V²/R; at 20V that's 0.4W through a 0.1W-rated resistor — it overheats and eventually burns)
• USB-C D+/D- must be shorted on the chip side for proper enumeration
• The USB-C connector requires careful reflow; loose joints cause intermittent communication

Fixes needed for a future revision:

• Use a power resistor rated for ≥0.4W (or ≥0.15W if limiting to 12V max)
• Short D+/D- on the CH224K side, remove the data line routing from the USB-C connector
• The firmware PD controller (PDController.h) is implemented but untested on hardware — only the hardware needs fixing before end-to-end testing can happen

Firmware

PlatformIO project targeting nologo_esp32c3_super_mini via the pioarduino fork (arduino-esp32 core 3.3.9, ESP-IDF 5.5.4).

Features

• HomeKit native — two dimmable lightbulbs (CH A/B) + one RGB lightbulb (NeoPixel), bridged accessory
• PD voltage switching — load-shedding before rail transition, NVS persistence for brown-out recovery (disabled until hardware fix)
• MQTT status — periodic JSON status publish, network voltage control via lightctrl/cmd/voltage
• Web Log — live status/log at http://<device-ip>/status
• Serial CLI — V0..V4 for PD voltage, J for status JSON, plus full HomeSpan command set
• OTA updates — via HomeSpan's built-in OTA

Building

1. Copy src/config.h.example → src/config.h
2. Edit config.h — set your WiFi credentials, HomeKit pairing code, MQTT broker IP, and NeoPixel count
3. Build and flash:

pio run -t upload
pio device monitor

Pin Map

Project Structure

├── src/
│   ├── main.cpp           # Setup, loop, serial commands, status LED
│   ├── config.h.example   # Configuration template (copy to config.h)
│   ├── Lights.h           # DimmableChannel + NeoStrip HomeKit services
│   ├── PDController.h     # CH224K PD voltage negotiation driver
│   └── StatusReporter.h   # MQTT publisher + JSON status builder
├── pcb/                   # KiCad 10 design files
│   ├── LEDController.kicad_sch   # Schematic
│   ├── LEDController.kicad_pcb   # PCB layout
│   ├── LEDController.kicad_pro   # Project file
│   ├── LEDController.csv         # BOM
│   ├── LEDController.pretty/     # Custom footprints (ESP32-C3 module, UCC27423)
│   ├── LedPannel.pretty/        # Custom footprints (PowerDI diode, inductor)
│   └── Prod/                    # Production Gerber files
└── platformio.ini

Dependencies

Credits

• PCB base design — Andrei (ihoneypot)
• Modifications, firmware, bringup — Yu-I (Hydr0neFN)

License

MIT