MatterHumiditySensor
About
The MatterHumiditySensor class provides a humidity sensor endpoint for Matter networks. This endpoint implements the Matter humidity sensing standard for read-only humidity reporting.
Features: * Humidity measurement reporting (0-100%) * 1/100th percent precision * Read-only sensor (no control functionality) * Automatic humidity updates * Integration with Apple HomeKit, Amazon Alexa, and Google Home * Matter standard compliance
Use Cases: * Room humidity monitoring * Weather stations * HVAC systems * Humidity logging * Smart home climate monitoring
API Reference
Constructor
Initialization
begin
Initializes the Matter humidity sensor endpoint with an initial humidity value.
bool begin(double humidityPercent = 0.00);
humidityPercent- Initial humidity percentage (0.0-100.0, default: 0.00)
This function will return true if successful, false otherwise.
Note: The implementation stores humidity with 1/100th percent precision internally. Values must be between 0.0 and 100.0.
Humidity Control
setHumidity
Sets the reported humidity percentage.
bool setHumidity(double humidityPercent);
humidityPercent- Humidity percentage (0.0-100.0)
This function will return true if successful, false otherwise.
Note: Humidity is stored with 1/100th percent precision. Values outside the 0.0-100.0 range will be rejected.
getHumidity
Gets the current reported humidity percentage.
double getHumidity();
This function will return the humidity percentage with 1/100th percent precision.
Example
Humidity 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.
*/
// Matter Manager
#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 Humidity Sensor Endpoint
MatterHumiditySensor SimulatedHumiditySensor;
// 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
// set your board USER BUTTON pin here - decommissioning button
const uint8_t buttonPin = BOOT_PIN; // Set your pin here. Using BOOT Button.
// Button control - decommision the Matter Node
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
// Simulate a humidity sensor - add your preferred humidity sensor library code here
float getSimulatedHumidity() {
// The Endpoint implementation keeps an uint16_t as internal value information,
// which stores data in 1/100th of humidity percent
static float simulatedHumidityHWSensor = 10.0;
// it will increase from 10% to 30% in 0.5% steps to simulate a humidity sensor
simulatedHumidityHWSensor = simulatedHumidityHWSensor + 0.5;
if (simulatedHumidityHWSensor > 30) {
simulatedHumidityHWSensor = 10;
}
return simulatedHumidityHWSensor;
}
void setup() {
// Initialize the USER BUTTON (Boot button) that will be used to decommission the Matter Node
pinMode(buttonPin, INPUT_PULLUP);
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
// set initial humidity sensor measurement
// Simulated Sensor - it shall initially print 95% and then move to the 10% to 30% humidity range
SimulatedHumiditySensor.begin(95.00);
// 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 Humidity 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.");
}
}
void loop() {
static uint32_t timeCounter = 0;
// Print the current humidity value every 5s
if (!(timeCounter++ % 10)) { // delaying for 500ms x 10 = 5s
// Print the current humidity value
Serial.printf("Current Humidity is %.02f%%\r\n", SimulatedHumiditySensor.getHumidity());
// Update Humidity from the (Simulated) Hardware Sensor
// Matter APP shall display the updated humidity percent
SimulatedHumiditySensor.setHumidity(getSimulatedHumidity());
}
// 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 (digitalRead(buttonPin) == HIGH && button_state) {
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 Humidity Sensor Matter Accessory. It shall be commissioned again.");
Matter.decommission();
}
delay(500);
}