MatterContactSensor
About
The MatterContactSensor class provides a contact sensor endpoint for Matter networks. This endpoint implements the Matter contact sensing standard for detecting open/closed states (e.g., doors, windows).
Features: * Contact state reporting (open/closed) * Simple boolean state * Read-only sensor (no control functionality) * Automatic state updates * Integration with Apple HomeKit, Amazon Alexa, and Google Home * Matter standard compliance
Use Cases: * Door/window sensors * Contact switches * Security systems * Access control * Smart home automation triggers
API Reference
Constructor
MatterContactSensor
Creates a new Matter contact sensor endpoint.
MatterContactSensor();
Initialization
begin
Initializes the Matter contact sensor endpoint. Fabric StateValue starts false (open). Call setContact() after Matter.begin() with the real sensor reading.
bool begin();
This function will return true if successful, false otherwise.
Typical usage:
ContactSensor.begin();
Matter.begin();
ContactSensor.setContact(digitalRead(contactPin));
end
Stops processing Matter contact sensor events.
void end();
Contact State Control
setContact
Sets the contact state. Call after Matter.begin().
bool setContact(bool _contactState);
_contactState- Contact state (true= closed,false= open)
This function will return true if successful, false otherwise.
getContact
Gets the current contact state.
bool getContact();
This function will return true if closed, false if open.
Operators
bool operator
Returns the current contact state.
operator bool();
Example:
if (mySensor) {
Serial.println("Contact is closed");
} else {
Serial.println("Contact is open");
}
Assignment operator
Sets the contact state. Same as setContact(); call after Matter.begin().
void operator=(bool _contactState);
Example:
mySensor = true; // Set contact to closed
mySensor = false; // Set contact to open
Example
Contact Sensor
// Copyright 2025 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/*
* This example is an example code that will create a Matter Device which can be
* commissioned and controlled from a Matter Environment APP.
* Additionally the ESP32 will send debug messages indicating the Matter activity.
* Turning DEBUG Level ON may be useful to following Matter Accessory and Controller messages.
*
* The example will create a Matter Contact Sensor Device.
* begin() creates the endpoint with StateValue open. Call setContact() after
* Matter.begin() with the real or simulated sensor reading.
* The Contact Sensor state will be indicated by the onboard LED.
* The Contact Sensor state will be simulated to change every simulatedSensorInterval.
*
* The onboard button can be kept pressed for 5 seconds to decommission the Matter Node.
* The example will also show the manual commissioning code and QR code to be used in the Matter environment.
*
*/
// Matter Manager
#include <Arduino.h>
#include <Matter.h>
#if !CONFIG_ENABLE_CHIPOBLE
// if the device can be commissioned using BLE, WiFi is not used - save flash space
#include <WiFi.h>
#endif
// List of Matter Endpoints for this Node
// Matter Contact Sensor Endpoint
MatterContactSensor ContactSensor;
// CONFIG_ENABLE_CHIPOBLE is enabled when BLE is used to commission the Matter Network
#if !CONFIG_ENABLE_CHIPOBLE
// WiFi is manually set and started
const char *ssid = "your-ssid"; // Change this to your WiFi SSID
const char *password = "your-password"; // Change this to your WiFi password
#endif
// LED will be used to indicate the Contact Sensor state
// set your board RGB LED pin here
#ifdef RGB_BUILTIN
const uint8_t ledPin = RGB_BUILTIN;
#else
const uint8_t ledPin = 2; // Set your pin here if your board has not defined LED_BUILTIN
#warning "Do not forget to set the RGB LED pin"
#endif
// set your board USER BUTTON pin here - decommissioning only
const uint8_t buttonPin = BOOT_PIN; // Set your pin here. Using BOOT Button.
// Button control
uint32_t button_time_stamp = 0; // debouncing control
bool button_state = false; // false = released | true = pressed
const uint32_t decommissioningTimeout = 5000; // keep the button pressed for 5s, or longer, to decommission
// Simulated hardware toggles every 20 seconds. Replace simulatedHWContactSensor() with a real probe read.
const uint32_t simulatedSensorInterval = 20000;
void setup() {
// Initialize the USER BUTTON (Boot button) that will be used to decommission the Matter Node
pinMode(buttonPin, INPUT_PULLUP);
// Initialize the LED (light) GPIO and Matter End Point
pinMode(ledPin, OUTPUT);
Serial.begin(115200);
// CONFIG_ENABLE_CHIPOBLE is enabled when BLE is used to commission the Matter Network
#if !CONFIG_ENABLE_CHIPOBLE
// Manually connect to WiFi
WiFi.begin(ssid, password);
// Wait for connection
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println();
#endif
// Create the endpoint. Fabric StateValue starts false (open); call setContact() after Matter.begin().
ContactSensor.begin();
digitalWrite(ledPin, LOW); // LED OFF
// Matter beginning - Last step, after all EndPoints are initialized
Matter.begin();
// Check Matter Accessory Commissioning state, which may change during execution of loop()
if (!Matter.isDeviceCommissioned()) {
Serial.println("");
Serial.println("Matter Node is not commissioned yet.");
Serial.println("Initiate the device discovery in your Matter environment.");
Serial.println("Commission it to your Matter hub with the manual pairing code or QR code");
Serial.printf("Manual pairing code: %s\r\n", Matter.getManualPairingCode().c_str());
Serial.printf("QR code URL: %s\r\n", Matter.getOnboardingQRCodeUrl().c_str());
// waits for Matter Contact Sensor Commissioning.
uint32_t timeCount = 0;
while (!Matter.isDeviceCommissioned()) {
delay(100);
if ((timeCount++ % 50) == 0) { // 50*100ms = 5 sec
Serial.println("Matter Node not commissioned yet. Waiting for commissioning.");
}
}
Serial.println("Matter Node is commissioned and connected to the network. Ready for use.");
}
}
bool simulatedHWContactSensor() {
// Simulated Contact Sensor. Replace this body with a real sensor, e.g. return digitalRead(contactPin);
static bool contactState = false;
static uint32_t lastTime = millis();
if (millis() - lastTime > simulatedSensorInterval) {
contactState = !contactState;
lastTime = millis();
}
return contactState;
}
void loop() {
// Check if the button has been pressed
if (digitalRead(buttonPin) == LOW && !button_state) {
// deals with button debouncing
button_time_stamp = millis(); // record the time while the button is pressed.
button_state = true; // pressed.
}
if (button_state && digitalRead(buttonPin) == HIGH) {
button_state = false; // released
}
// Onboard User Button is kept pressed for longer than 5 seconds in order to decommission matter node
uint32_t time_diff = millis() - button_time_stamp;
if (button_state && time_diff > decommissioningTimeout) {
Serial.println("Decommissioning Contact Sensor Matter Accessory. It shall be commissioned again.");
Matter.decommission();
button_time_stamp = millis(); // avoid running decommissioning again, reboot takes a second or so
}
// Report simulated (or real) hardware to Matter. First call after Matter.begin() applies the current reading.
bool previous = ContactSensor.getContact();
ContactSensor.setContact(simulatedHWContactSensor());
if (ContactSensor.getContact() != previous) {
Serial.printf("Contact Sensor is %s.\r\n", ContactSensor ? "Closed" : "Open");
}
digitalWrite(ledPin, ContactSensor ? HIGH : LOW);
delay(50);
}