DimmerLink — User Documentation

AC dimmer controller for lamp brightness control via TRIAC. Connects to your project (Arduino, ESP32, Raspberry Pi, etc.) and allows you to control AC dimmers with simple commands.

Working with DimmerLink is easy.

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Table of Contents

Section	Description
Quick Start	Start here — minimal example in 5 minutes
Hardware Connection	Wiring diagrams for popular boards
UART Interface	Commands and examples for UART
I2C Interface	Registers and examples for I2C
Single Board Computers	Raspberry Pi, Orange Pi, Banana Pi
Advanced Usage	USB-UART, LoRa, GSM, Bluetooth
ESPHome integration	AC dimming for Home Assistant
FAQ & Troubleshooting	Common questions and solutions

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• Product Page: DimmerLink on rbdimmer.com
• AliExpress Page: DimmerLink on AliExpress

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Key Features

✅ FLICKER-FREE — Dedicated Cortex-M+ handles all critical timings. No software delays, interrupt conflicts, or flickering.

✅ NO LIBRARIES REQUIRED — Send simple 3-4 byte commands via UART or I2C. Works with any programming language. Literally 5 lines of code.

✅ UNIVERSAL COMPATIBILITY — Arduino, ESP32, ESP8266, Raspberry Pi, STM32, any MCU with UART/I2C. Supports 1.8V, 3.3V, 5V logic levels.

✅ BRIGHTNESS CONTROL — 0-100% range

✅ DIMMING CURVES — Linear, RMS (for incandescent), Logarithmic. Auto-detection of 50/60Hz mains frequency.

✅ MAINS DETECTION — Automatic mains frequency detection (50/60 Hz)

✅ DUAL INTERFACE — UART (115200 8N1) or I2C. Switch by command at any time.

✅ ULTRA-COMPACT — Only 18×12mm. Standard 0.1" pins. Fits in any enclosure.

✅ PLUG & PLAY — Connect, power up, send command. Working dimmer in 5 minutes.

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The Problem We Solve

Every maker knows this pain: you add an AC dimmer library to your project, and suddenly your lamps start flickering, timings go haywire, and you spend hours debugging interrupt conflicts. DimmerLink completely eliminates this problem by offloading all time-critical operations to a dedicated Cortex-M+ microcontroller.

How It Works

Connect DimmerLink between your controller (Arduino, ESP32, Raspberry Pi, or any MCU) and an AC dimmer module. Send a 3-byte command like SET 50% via UART or write a value to an I2C register. The controller handles zero-cross detection, calculates phase angle, and controls the TRIAC with microsecond precision. No libraries. No interrupts. No conflicts with your code.

Or connect to remote transmission modules like LoRa, GSM/GPRS, Bluetooth or WiFi bridges, or simply to your PC via USB-UART modules like CH340, CP2102/CP2104. Industrial RS-232 modules. No code required, just commands via terminal.

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Which Interface to Choose?

Criteria	UART	I2C
Connection simplicity	2 wires + power	2 wires + power
Speed	115200 baud	100 kHz
Multiple devices	No	Yes (different addresses)
Works with bridges	Yes (USB-UART, WiFi, LoRa)	Limited
Recommendation	For remote control	For local control

💡 Tip: We recommend I2C for beginners — simpler code, clearer structure.

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Compatibility

DimmerLink supports 1.8V, 3.3V and 5V logic levels — direct connection without level converters!

Platform	UART	I2C	Logic Level
Arduino Uno/Nano	✓	✓	5V ✓
Arduino Mega	✓	✓	5V ✓
ESP8266	✓	✓	3.3V ✓
ESP32	✓	✓	3.3V ✓
STM32 (Blue Pill)	✓	✓	3.3V ✓
Raspberry Pi Pico	✓	✓	3.3V ✓
Raspberry Pi 3/4/5	✓	✓	3.3V ✓
Orange Pi	✓	✓	3.3V ✓
Banana Pi	✓	✓	3.3V ✓
ATtiny, nRF52, MSP430	✓	✓	1.8V ✓

This is just a basic list — DimmerLink works with any microcontroller that has UART or I2C!

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Quick Example

Arduino + I2C — set brightness to 50%:

#include <Wire.h>

void setup() {
    Wire.begin();

    // Set brightness to 50%
    Wire.beginTransmission(0x50);
    Wire.write(0x10);  // Brightness register
    Wire.write(50);    // 50%
    Wire.endTransmission();
}

void loop() {}

Python + UART:

import serial

ser = serial.Serial('/dev/ttyUSB0', 115200)
ser.write(bytes([0x02, 0x53, 0x00, 50]))  # SET dimmer 0 to 50%
response = ser.read(1)
print("OK" if response[0] == 0 else "Error")

Serial Terminal Example:

1. Port → select your COM port
2. Baud: 115200
3. Send → "Send Numbers" tab
4. Enter: 02 53 00 32 or 0x02 0x53 0x00 0x32 (HEX 32 is 50 in decimal)
5. Click "Send Numbers"

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Code Examples

Ready-to-use examples are located in the examples/ folder:

examples/
├── arduino/
│   ├── uart_basic.ino
│   └── i2c_basic.ino
├── python/
│   ├── uart_example.py
│   └── i2c_example.py
└── micropython/
    ├── uart_example.py
    └── i2c_example.py

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Support

• GitHub Issues: Report an issue
• Product Page: DImmerLink on rbdimmer.com
• AliExpress Page: DImmerLink on AliExpress

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Documentation Version: 1.0 Date: 2026-01