esp32-core/libraries/Matter/examples/MatterTemperatureLight

Matter Color Temperature Light Example

This example demonstrates how to create a Matter-compatible color temperature light device using an ESP32 SoC microcontroller.
The application showcases Matter commissioning, device control via smart home ecosystems, and manual control using a physical button. The color temperature light provides warm white to cool white control with adjustable brightness.

Supported Targets

SoC	Wi-Fi	Thread	BLE Commissioning	RGB LED	Status
ESP32	✅	❌	❌	Required	Fully supported
ESP32-S2	✅	❌	❌	Required	Fully supported
ESP32-S3	✅	❌	✅	Required	Fully supported
ESP32-C3	✅	❌	✅	Required	Fully supported
ESP32-C5	❌	✅	✅	Required	Supported (Thread only)
ESP32-C6	✅	❌	✅	Required	Fully supported
ESP32-H2	❌	✅	✅	Required	Supported (Thread only)

Note on Commissioning:

• ESP32 & ESP32-S2 do not support commissioning over Bluetooth LE. For these chips, you must provide Wi-Fi credentials directly in the sketch code so they can connect to your network manually.
• ESP32-C6 Although it has Thread support, the ESP32 Arduino Matter Library has been pre compiled using Wi-Fi only. In order to configure it for Thread-only operation it is necessary to build the project using Arduino as an IDF Component and to disable the Matter Wi-Fi station feature.
• ESP32-C5 Although it has Wi-Fi 2.4 GHz and 5 GHz support, the ESP32 Arduino Matter Library has been pre compiled using Thread only. In order to configure it for Wi-Fi operation it is necessary to build the project using Arduino as an ESP-IDF component and disable Thread network, keeping only Wi-Fi station.

Features

• Matter protocol implementation for a color temperature light device
• Support for both Wi-Fi and Thread(*) connectivity
• Color temperature control (warm white to cool white, 100-500 mireds)
• Brightness level control (0-255)
• State persistence using Preferences library
• Button control for toggling light and factory reset
• RGB LED support with color temperature to RGB conversion
• Regular LED support with PWM brightness control
• Matter commissioning via QR code or manual pairing code
• Integration with Apple HomeKit, Amazon Alexa, and Google Home (*) It is necessary to compile the project using Arduino as IDF Component.

Hardware Requirements

• ESP32 compatible development board (see supported targets table)
• RGB LED connected to GPIO pins (or using built-in RGB LED), or regular LED for PWM brightness control
• User button for manual control (uses BOOT button by default)

Pin Configuration

• RGB LED: Uses RGB_BUILTIN if defined, otherwise pin 2
• Button: Uses BOOT_PIN by default

Software Setup

Prerequisites

1. Install the Arduino IDE (2.0 or newer recommended)
2. Install ESP32 Arduino Core with Matter support
3. ESP32 Arduino libraries:
   • Matter
   • Preferences
   • Wi-Fi (only for ESP32 and ESP32-S2)

Configuration

Before uploading the sketch, configure the following:

1. Wi-Fi credentials (if not using BLE commissioning - mandatory for ESP32 | ESP32-S2):

   const char *ssid = "your-ssid";         // Change to your Wi-Fi SSID
   const char *password = "your-password"; // Change to your Wi-Fi password
   

2. LED pin configuration (if not using built-in RGB LED):

   const uint8_t ledPin = 2;  // Set your RGB LED pin here
   

3. Button pin configuration (optional): By default, the BOOT button (GPIO 0) is used for the Light On/Off manual control. You can change this to a different pin if needed.

   const uint8_t buttonPin = BOOT_PIN;  // Set your button pin here
   

Building and Flashing

1. Open the MatterTemperatureLight.ino sketch in the Arduino IDE.
2. Select your ESP32 board from the Tools > Board menu.

3. Select "Huge APP (3MB No OTA/1MB SPIFFS)" from Tools > Partition Scheme menu.

4. Enable "Erase All Flash Before Sketch Upload" option from Tools menu.
5. Connect your ESP32 board to your computer via USB.
6. Click the Upload button to compile and flash the sketch.

Expected Output

Once the sketch is running, open the Serial Monitor at a baud rate of 115200. The Wi-Fi connection messages will be displayed only for ESP32 and ESP32-S2. Other targets will use Matter CHIPoBLE to automatically setup the IP Network. You should see output similar to the following, which provides the necessary information for commissioning:

Connecting to your-wifi-ssid
.......
Wi-Fi connected
IP address: 192.168.1.100

Matter Node is not commissioned yet.
Initiate the device discovery in your Matter environment.
Commission it to your Matter hub with the manual pairing code or QR code
Manual pairing code: 34970112332
QR code URL: https://project-chip.github.io/connectedhomeip/qrcode.html?data=MT%3A6FCJ142C00KA0648G00
Matter Node not commissioned yet. Waiting for commissioning.
Matter Node not commissioned yet. Waiting for commissioning.
...
Initial state: ON | brightness: 15 | Color Temperature: 454 mireds
Matter Node is commissioned and connected to the network. Ready for use.
Light OnOff changed to ON
Light Brightness changed to 128
Light Color Temperature changed to 370

Using the Device

Manual Control

The user button (BOOT button by default) provides manual control:

• Short press of the button: Toggle light on/off
• Long press (>5 seconds): Factory reset the device (decommission)

Color Temperature Control

The light supports color temperature adjustment from warm white to cool white:

• Warm White: Higher mired values (400-500 mireds) - warmer, more yellow light
• Cool White: Lower mired values (100-200 mireds) - cooler, more blue light
• Default: 454 mireds (Warm White)

The color temperature is stored in Preferences and restored after power cycles.

Brightness Control

The light supports brightness adjustment from 0 to 255:

• 0: Light is off
• 1-254: Various brightness levels
• 255: Maximum brightness
• Default: 15 (~6% brightness)

The brightness level is stored in Preferences and restored after power cycles.

Smart Home Integration

Use a Matter-compatible hub (like an Apple HomePod, Google Nest Hub, or Amazon Echo) to commission the device.

Apple Home

1. Open the Home app on your iOS device
2. Tap the "+" button > Add Accessory
3. Scan the QR code displayed in the Serial Monitor, or
4. Tap "I Don't Have a Code or Cannot Scan" and enter the manual pairing code
5. Follow the prompts to complete setup
6. The device will appear as a color temperature light in your Home app
7. You can adjust the color temperature (warm/cool) and brightness from the Home app

Amazon Alexa

1. Open the Alexa app
2. Tap More > Add Device > Matter
3. Select "Scan QR code" or "Enter code manually"
4. Complete the setup process
5. The light will appear in your Alexa app
6. You can control color temperature and brightness using voice commands or the app

Google Home

1. Open the Google Home app
2. Tap "+" > Set up device > New device
3. Choose "Matter device"
4. Scan the QR code or enter the manual pairing code
5. Follow the prompts to complete setup
6. You can adjust color temperature and brightness from the Google Home app

Code Structure

The MatterTemperatureLight example consists of the following main components:

1. setup(): Initializes hardware (button, LED), configures Wi-Fi (if needed), sets up the Matter Color Temperature Light endpoint, restores the last known state from Preferences (on/off, brightness, color temperature), and registers callbacks for state changes.

2. loop(): Checks the Matter commissioning state, handles button input for toggling the light and factory reset, and allows the Matter stack to process events.

3. Callbacks:

   • setLightState(): Controls the physical LED. For RGB LEDs, converts color temperature (mireds) to RGB color and applies brightness. For regular LEDs, uses PWM brightness control.
   • onChangeOnOff(): Handles on/off state changes and logs to Serial Monitor.
   • onChangeBrightness(): Handles brightness changes and logs to Serial Monitor.
   • onChangeColorTemperature(): Handles color temperature changes and logs to Serial Monitor.

4. State Persistence: Uses Preferences library to store and restore:

   • On/off state (default: ON if not previously stored)
   • Brightness level (default: 15 if not previously stored)
   • Color temperature in mireds (default: 454 mireds - Warm White if not previously stored)

Troubleshooting

• Device not visible during commissioning: Ensure Wi-Fi or Thread connectivity is properly configured
• RGB LED not responding: Verify pin configurations and connections. For RGB LEDs, ensure the board defines RGB_BUILTIN or set the pin manually
• LED not showing color temperature correctly: RGB LED conversion uses espCTToRgbColor() function. For regular LEDs, only brightness is controlled via PWM
• Color temperature not changing: Verify that color temperature is within valid range (100-500 mireds). Check Serial Monitor for callback messages
• Brightness not responding: Ensure LED pin supports PWM output. Check Serial Monitor for brightness change messages
• State not persisting: Verify Preferences library is working correctly. Check that flash memory is not full
• Failed to commission: Try factory resetting the device by long-pressing the button. Other option would be to erase the SoC Flash Memory by using Arduino IDE Menu -> Tools -> Erase All Flash Before Sketch Upload: "Enabled" or directly with esptool.py --port <PORT> erase_flash
• No serial output: Check baudrate (115200) and USB connection

Related Documentation

• Matter Overview
• Matter Endpoint Base Class
• Matter Color Temperature Light Endpoint

License

This example is licensed under the Apache License, Version 2.0.