WiFi-Controlled RGB Power Lamp

This repository documents the design and implementation of a WiFi-controlled RGB lamp using discrete power electronics and embedded systems. The lamp is based on 3× 5W LEDs (RGB), driven by LM3404 constant-current drivers, monitored by INA226 current sensors, and controlled by an ESP8266 microcontroller via a custom web interface.

Overview

• Microcontroller: ESP8266 (ESP-12E)
• LED Drivers: LM3404, one per color channel
• Current Sensors: INA226 (I²C), one per channel
• Power Supply: 24V DC input, regulated to 5V and 3.3V
• User Interface: Web application hosted on ESP8266 for RGB control and power monitoring

System Architecture

Block Diagram:

Web Interface

• RGB control using Vue-based color picker
• Adjustable brightness slider (mapped to PWM)
• Real-time current monitoring (INA226)
• Basic animation mode (rainbow sequence)

Web UI Screenshot:

PCB Design

• 2-layer FR4 PCB with thermal copper pours and via stitching
• Test points for PWM, switch nodes, and sense lines
• FFC interface for external programmer
• Custom CH340C programming board (USB → UART)

gerber View:

3D Render:

Finished product:

Testing and Analysis

Thermal Imaging

• Thermal images captured using Fluke thermal camera
• Red LED remains coolest; green and blue require better cooling
• Thermal deviation from calculated values due to PCB/slug bonding

Thermal Measurement Example:

Oscilloscope Measurements

• Switching ripple observed and confirmed within expected range
• DCM ringing noted at switch nodes; no impact on operation

Known Issues & Improvements

• DIM Pin Fix: Initial circuit caused full brightness during MCU boot. Fixed with pulldown resistor.
• I²C Line Reversal: SDA/SCL reversed in layout; resolved via software GPIO reassignment.
• Thermal Solution: Future revisions should consider external heatsink or aluminum-core PCB.