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 Home Assistant, Apple Home, 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

MatterHumiditySensor

Creates a new Matter humidity sensor endpoint.

MatterHumiditySensor();

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.

end

Stops processing Matter humidity sensor events.

void end();

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.

Operators

double operator

Returns the current humidity percentage.

operator double();

Example:

double humidity = mySensor;  // Get current humidity

Assignment operator

Sets the humidity percentage.

void operator=(double humidityPercent);

Example:

mySensor = 45.5;  // Set humidity to 45.5%

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 <Arduino.h>
#include <Matter.h>
// List of Matter Endpoints for this Node
// Matter Humidity Sensor Endpoint
MatterHumiditySensor SimulatedHumiditySensor;

// Wi-Fi credentials for this sketch. Fill these in when the board cannot
// commission over BLE (Arduino prebuild on ESP32 / ESP32-S2): the sketch
// joins the AP itself. When Matter commissions over BLE (CHIPoBLE), the
// hub sends SSID and password — leave the placeholders; they are unused.
#define WIFI_SSID     "your-ssid"
#define WIFI_PASSWORD "your-password"

// set your board USER BUTTON pin here - decommissioning button
const uint8_t buttonPin = BOOT_PIN;  // Set your pin here. Using BOOT Button.
MatterButton button;

// 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
  button.begin(buttonPin);

  Serial.begin(115200);

// CONFIG_ENABLE_CHIPOBLE=n: sketch starts Wi-Fi here; with CHIPoBLE the hub delivers credentials.
#if !CONFIG_ENABLE_CHIPOBLE
  matterConnectWiFi(WIFI_SSID, WIFI_PASSWORD);
#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();
  matterWaitUntilReady();
}

void loop() {
  matterRestartIfNoFabric();

  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());
  }

  matterButtonEvent_t ev;
  while ((ev = button.poll()) != MATTER_BUTTON_NONE) {
    if (ev == MATTER_BUTTON_LONG_HOLD) {
      Serial.println("Decommissioning Humidity Sensor Matter Accessory. It shall be commissioned again.");
      Matter.decommission();
    }
  }

  delay(500);
}