Matter and Thread with ESP32

From ChatGPT:

Below is a step-by-step guide and example setup showing how you might structure an ESP32-based Matter + Thread project using the Arduino framework within VS Code and PlatformIO. This is a conceptual walkthrough intended for beginners who are totally new to Matter and Thread. Please note that Matter and Thread support for Arduino on ESP32 is still quite limited and experimental. The code and steps below are for illustrative purposes, showing how you would approach organizing such a project. Actual implementation may require additional tooling, libraries, and following the evolving Matter ecosystem.

Prerequisites

Hardware:
- An ESP32 development board (e.g., ESP32-DevKitC).
- A Thread Border Router on your network (such as an Apple HomePod mini, Google Nest Hub (2nd gen), or a dedicated Thread border router device).
Software / Tools:
- Visual Studio Code
- PlatformIO IDE extension for VS Code
- Git for cloning repositories if needed.
- A current Arduino framework installed via PlatformIO’s ESP32 platform.
- Experimental Matter Arduino support (this might require manually integrating libraries from the Matter SDK or a third-party Arduino-compatible Matter library if one becomes available).
Knowledge Assumptions:
- No prior Matter or Thread experience is required, but expect that this process is not yet straightforward. You may need to refer to official Matter documentation and repositories.
- Some familiarity with Arduino programming basics (setup/loop functions, pinMode, digitalWrite, etc.) will help.

Project Structure

Your PlatformIO project might look like this:

my-matter-project/
├─ src/
│  └─ main.ino
├─ platformio.ini
└─ lib/
   └─ (possible Matter/Thread libraries)

main.ino: Your Arduino sketch file where you initialize Matter, connect to Thread, and implement your logic (e.g., toggling a light, reading a temperature sensor).
platformio.ini: Configuration file for PlatformIO.
lib/: Any additional libraries, including Matter or Thread libraries if you have them locally.

Example `platformio.ini`

In platformio.ini, specify the board, framework, and any additional flags or libraries needed. Note that the example below is conceptual. You will need actual libraries once they are available.

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino

; Additional flags and libraries might be needed for Matter and Thread
lib_deps =
  ; Add any libraries that provide Matter/Thread support if available
  ; Example (fictional): https://github.com/someuser/arduino-matter-lib.git

build_flags =
  -DMATTER_ENABLED
  -DTHREAD_ENABLED

MATTER_ENABLED and THREAD_ENABLED are example macros you might use in code to conditionally compile Matter/Thread-specific code if libraries are integrated.

Conceptual Steps to Enable Matter and Thread

Install Matter Dependencies (Hypothetical):
- Since official Arduino support for Matter is limited, you may need to:
  - Clone the Matter repository.
  - Build or adapt a lightweight Matter library for Arduino.
  - Copy it into the lib/ folder or reference it from an online source.
Set Up Thread Connectivity:
- Ensure your ESP32 hardware or variant supports 802.15.4 (for Thread). The vanilla ESP32 does not support Thread radio directly; you may need a specialized module like the ESP32-H2.
- If using a co-processor or a different board that supports Thread, integrate the Thread stack (through a provided library if available).
Commissioning the Device with Matter:
- In Matter, devices must be commissioned (paired) before control is possible.
- During commissioning, the device will advertise a QR code or a numeric setup code. You will use the Apple Home app or another Matter-compatible controller on your iPhone to add this device.
Implement Clusters (On/Off and Temperature):
- Matter defines "clusters" (functional blocks like On/Off or TemperatureMeasurement).
- Your code will set up these clusters, respond to commands from the iPhone, and update attributes.

Example `main.ino` (Conceptual Pseudocode)

Note: The actual Matter/Thread APIs will differ based on the library you integrate. The code below is a high-level example showing the general structure.

#include <Arduino.h>
// Hypothetical Matter and Thread headers
#include <Matter.h>
#include <ThreadNetwork.h>

// Pins for demonstration (adjust as needed)
const int LIGHT_PIN = 2;  // GPIO pin connected to an LED
float currentTemperature = 22.5; // Mock temperature value

// Callback when On/Off attribute changes from the controller (iPhone)
void OnOffClusterCallback(bool on)
{
    digitalWrite(LIGHT_PIN, on ? HIGH : LOW);
    Serial.printf("Light turned %s by Matter command.\n", on ? "ON" : "OFF");
}

// Function to update the temperature attribute periodically
void UpdateTemperatureAttribute()
{
    // In a real scenario, read from a sensor:
    // currentTemperature = readTemperatureSensor();
    
    Matter.setTemperature(currentTemperature);
    Serial.printf("Updated temperature: %.2f°C\n", currentTemperature);
}

void setup() {
    Serial.begin(115200);
    pinMode(LIGHT_PIN, OUTPUT);
    digitalWrite(LIGHT_PIN, LOW);

    // Initialize Wi-Fi or Ethernet if needed for commissioning.
    // Thread initialization (this depends on hardware support):
    if (!ThreadNetwork.begin()) {
        Serial.println("Failed to initialize Thread network. Check hardware and config.");
    } else {
        Serial.println("Thread network initialized.");
    }

    // Initialize Matter stack
    if (!Matter.begin()) {
        Serial.println("Failed to initialize Matter stack!");
        return;
    }

    // Configure Matter device details (vendor ID, product ID, etc.)
    Matter.setVendorId(0xFFF1);
    Matter.setProductId(0x8000);
    
    // Initialize On/Off cluster
    Matter.onOffCluster().setCallback(OnOffClusterCallback);

    // Initialize Temperature Measurement cluster
    Matter.temperatureCluster().setInitialValue(currentTemperature);

    // Start advertising for commissioning. The user will add this device
    // to the Apple Home app by scanning a QR code or entering a setup code.
    if (!Matter.startCommissioning()) {
        Serial.println("Failed to start commissioning.");
    } else {
        Serial.println("Commissioning started. Open Apple Home and add accessory.");
    }
}

void loop() {
    // Run Matter event handling
    Matter.loop();

    // Periodically update the temperature value
    static unsigned long lastUpdate = 0;
    if (millis() - lastUpdate > 5000) { // every 5 seconds
        UpdateTemperatureAttribute();
        lastUpdate = millis();
    }

    delay(100);
}

What’s Happening Here?

Setup:
- Start Serial communication for debugging.
- Initialize hardware (LED pin for a "light").
- Initialize Thread network (requires appropriate hardware support).
- Initialize the Matter stack and configure clusters.
Commissioning:
- Start commissioning mode. On your iPhone’s Home app, you would scan the provided QR code or use a setup code to add this device. After commissioning, the iPhone can send On/Off commands and read the temperature attribute.
Main Loop:
- Matter.loop() handles incoming Matter messages.
- Every few seconds, UpdateTemperatureAttribute() simulates reading a temperature sensor and updates the Matter attribute so the iPhone can read it.

Next Steps & Troubleshooting

Adjusting the Code for Real Hardware:
If you have a real temperature sensor (e.g., an I2C temperature sensor), integrate that code into UpdateTemperatureAttribute().
Thread and Matter Libraries:
The biggest challenge is currently finding or integrating stable Arduino Matter/Thread libraries. Keep an eye on the Matter project’s GitHub and related community forums for updates.
Commissioning the Device:
Follow Apple’s instructions for adding a Matter accessory to Home. This typically involves tapping "Add Accessory" and scanning a QR code. Your code should print a URL or numeric setup code. You may need a display or to print the QR code in the terminal as ASCII, or provide the code manually.
Debugging:
Use Serial.println() statements liberally to see what’s happening at each step. If something fails, double-check configurations, ensure you have the right hardware for Thread, and confirm that your Thread Border Router is operational.

Conclusion

This guide provided a conceptual overview of setting up a Matter + Thread project with an ESP32 using PlatformIO and Arduino framework in VS Code. While the example code won’t run as-is due to the experimental nature of Matter/Thread support on Arduino, it outlines the approach, structure, and logic flow you would use. As the ecosystem matures and official libraries become available, you’ll be able to refine and adapt this code into a working solution.

brennanMKE/README.md