LED CCT Controller

ESP32-based LED Color Temperature (CCT) controller, designed for integration with Home Assistant via ESPHome.

Overview

This project controls white-tunable ("CCT") LED strips, allowing automatic adjustment of color temperature (2700K-5000K) throughout the day. Inspired by f.lux screen color shifting, but applied to room lighting.

The controller integrates with Home Assistant for location-based automations and calendar-aware scheduling (e.g., adjusting color temperature based on work schedule).

Hardware Versions

v1.0 -- Dev Board Prototype

Uses an ESP32 DEVKIT V1 development board with external 3.3V buck converter module.

Components:

• ESP32 DEVKIT V1 (DOIT)
• 2x IRLB8721PBF N-Channel MOSFETs (TO-220)
• 4-pin header for buck converter module
• Wire pads for power and LED connections

v2.0 -- Standalone Module

Replaces the dev board with a bare ESP-WROOM-02D WiFi module and integrates the voltage regulator on-board using an LP2985-33DBVR (3.3V LDO, SOT-23-5).

Changes from v1.0:

• Replaced ESP32 DEVKIT V1 with ESP-WROOM-02D (4MB) module
• Added on-board LP2985-33DBVR 3.3V LDO voltage regulator (replaces external buck converter)
• Added decoupling capacitors (10uF, 0.1uF) for ESP module and regulator
• Added 10K pull-up resistors for boot/reset lines
• Added IO0 wire pad for programming mode
• Added serial header (JP1) for TXD/RXD programming
• Moved to SMD passives (1206 package)

Circuit Design

Power

• Input: 12V DC power supply
• LED strips are driven at 12V through N-channel MOSFETs
• 3.3V rail for ESP module:
  • v1.0: External 3.3V buck converter module (up to 21V input)
  • v2.0: On-board LP2985-33DBVR LDO

LED Control

Two PWM channels (warm white + cool white) drive separate MOSFET switches:

• Transistors: IRLB8721PBF N-channel power MOSFETs (TO-220)
  • Rds(on): 8.7 mOhm at 4.5V Vgs
  • Gate threshold: max 2.35V (compatible with 3.3V logic)
  • Continuous drain current: 62A (well above the ~1A needed)
• LED Strip: 5m Tunable White LED Strip, 12V from SuperBright LEDs (13.8 W/m)

ESPHome Configuration

This board is designed for use with ESPHome's CWWW Light platform, which provides cool white + warm white light mixing with color temperature control.

File Structure

hardware/
  v1.0/
    Power Board.sch      -- EAGLE schematic
    Power Board.brd      -- EAGLE board layout
    BOM.csv              -- Bill of materials
    CAMOutputs/          -- Gerber files for fabrication
  v2.0/
    Power Board.sch      -- EAGLE schematic
    Power Board.brd      -- EAGLE board layout
    BOM.csv              -- Bill of materials
    CAMOutputs/          -- Gerber files for fabrication
  images/                -- Rendered schematic and board SVGs

License

MIT