Lire les données d’un capteur de temperature Xiaomi avec un Arduino Nano ESP32 via BLE

// Monitor Xiaomi Mi Temperature and Humidity Monitor 2
// with Arduino Nano ESP32 and Arduino Cloud
// https://tutoduino.fr/
// Copyleft 2023
#include "thingProperties.h"
#include <ArduinoBLE.h>
// Bluetooth Low Energy Mi Temperature and Humidity Service
const char* miServiceUUID = "ebe0ccb0-7a0a-4b0c-8a1a-6ff2997da3a6";
// Bluetooth Low Energy Mi Temperature and Humidity Characteristic
const char* miCharacteristicUUID = "ebe0ccc1-7a0a-4b0c-8a1a-6ff2997da3a6";
// Variables used for periodic reading
unsigned long previousMillis = 0;
unsigned long currentMillis = 0;
unsigned long period = 3600000;
// State of the BLE connexion
enum state_t {
  INIT_STATE,
  SCANNING_STATE,
  ALL_PERIPHERAL_FOUND_STATE,
  RUNNING_STATE
};
state_t state = INIT_STATE;
// Number of Mi Temperature and Humidity Monitor 2 peripherals we want to monitor
#define NUMBER_OF_SENSORS 2
// Number of Mi Temperature and Humidity Monitor 2 peripherals found during BLE scanning
uint8_t nbMiTempPeripheralFound = 0;
// Global variable to store BLE devices found during scanning
BLEDevice peripheral[NUMBER_OF_SENSORS];
// Function to disconnect all peripherals found during BLE scanning
void disconnectAllPeripherals() {
  for (int sensor = 0; sensor < nbMiTempPeripheralFound; sensor++) {
    // Check if peripheral is connected
    if (peripheral[sensor].connected()) {
      // Disconnect peripheral
      peripheral[sensor].disconnect();
    }
  }
}
// Function to stop BLE scanning and disconnect all peripherals
// that are connected
void stopScanMiPeripheral() {
  // Stop BLE scanning
  BLE.stopScan();
  // Disconnect from peripherals
  disconnectAllPeripherals();
  // Leave ALL_PERIPHERAL_FOUND_STATE state to enter RUNNING_STATE
  state = RUNNING_STATE;
}
// BLE scan and connect to Mi Temperature and Humidity Monotor 2 peripherals
// Discover exposed services and check if required temperature and humidity
// characteristics are available on these peripherals
uint8_t scanMiPeripheral() {
  peripheral[nbMiTempPeripheralFound] = BLE.available();
  if (peripheral[nbMiTempPeripheralFound]) {
    // Check if the peripheral is a Mi Temperature and Humidity Monitor 2 peripheral
    if (peripheral[nbMiTempPeripheralFound].hasLocalName()) {
      if (peripheral[nbMiTempPeripheralFound].localName() == "LYWSD03MMC") {
        Serial.print("Discovered a Mi Temperature and Humidity Monitor 2, address : ");
        Serial.println(peripheral[nbMiTempPeripheralFound].address());
        // Connect to the peripheral (try it twice)
        if (peripheral[nbMiTempPeripheralFound].connect()) {
        } else {
          Serial.println("Failed to connect, disconnect and try again!");
          peripheral[nbMiTempPeripheralFound].disconnect();
          if (peripheral[nbMiTempPeripheralFound].connect()) {
            Serial.println("Connected");
          } else {
            Serial.println("Failed to connect!");
            return 1;
          }
        }
        // Peripheral is connected, discover exposed services and check if temperature
        // and humidity characteristic is available
        if (peripheral[nbMiTempPeripheralFound].discoverService(miServiceUUID)) {
          if (!peripheral[nbMiTempPeripheralFound].characteristic(miCharacteristicUUID)) {
            Serial.println("Characteristic not found!");
            peripheral[nbMiTempPeripheralFound].disconnect();
            return 1;
          }
          // Required characteristic has been found for this peripheral
          Serial.println("Sensor ok");
          nbMiTempPeripheralFound++;
        }
      }
    }
  }
  // Change state to ALL_PERIPHERAL_FOUND_STATE if all peripherals have been discovered
  if ((nbMiTempPeripheralFound == NUMBER_OF_SENSORS) && (state == SCANNING_STATE)) {
    state = ALL_PERIPHERAL_FOUND_STATE;
    Serial.println("All sensors found");
  }
  return 0;
}
// Connect to Mi Temperature and Humidity Monotor 2 peripherals
// and read Temperature, Humidity and Battery data
void connectAndReadData() {
  float temp, hum, batt;
  uint8_t value[5];
  // The connection and read is only done in RUNNING_STATE
  if (state == RUNNING_STATE) {
    for (int sensor = 0; sensor < nbMiTempPeripheralFound; sensor++) {
      if (peripheral[sensor].connect()) {
        if (peripheral[sensor].discoverService(miServiceUUID)) {
          peripheral[sensor].characteristic(miCharacteristicUUID).readValue(value, 5);
          temp = ((float)(value[1] << 8) + (float)value[0]) / 100;
          hum = (float)value[2];
          batt = ((float)(value[4] << 8) + (float)value[3]) / 1000;
          Serial.print("Temp = ");
          Serial.print(temp);
          Serial.print(" ");
          Serial.print("Hum = ");
          Serial.print(hum);
          Serial.print(" ");
          Serial.print("Batt = ");
          Serial.print(batt);
          Serial.println();
          if (sensor == 0) {
            temperature = temp;
            batterie = batt;
          }
          if (sensor == 1) {
            temperature2 = temp;
            batterie2 = batt;
          }
          // Once date is read, disconnect from peripheral
          peripheral[sensor].disconnect();
        }
      }
    }
  }
}
void setup() {
  // Start serial port monitor
  Serial.begin(9600);
  delay(1500);
  // BLE initialization
  if (!BLE.begin()) {
    Serial.println("Starting Bluetooth® Low Energy module failed!");
    while (1) {};
  }
  Serial.println("Bluetooth® Low Energy module started");
  // Start scanning for BLE peripheral
  BLE.scan();
  state = SCANNING_STATE;
  // Init Arduino IoT Cloud
  initProperties();
  // Connect to Arduino IoT Cloud
  ArduinoCloud.begin(ArduinoIoTPreferredConnection);
  setDebugMessageLevel(2);
  ArduinoCloud.printDebugInfo();
}
void loop() {
  switch (state) {
    case SCANNING_STATE:
      // Scan BLE peripherals to find Mi Temperature and Humidity Monitor 2 peripherals
      scanMiPeripheral();
      break;
    case ALL_PERIPHERAL_FOUND_STATE:
      // Stop BLE scanning once all Mi Temperature and Humidity Monitor 2 peripherals have been found
      stopScanMiPeripheral();
      // Connect to Mi Temperature and Humidity Monitor 2 peripherals
      // and read Temperature, Humidity and Battery data
      connectAndReadData();
      break;
    case RUNNING_STATE:
      // Periodically connect to Mi Temperature and Humidity Monitor 2 peripherals
      // and read Temperature, Humidity and Battery data
      currentMillis = millis();
      if (currentMillis - previousMillis >= period) {
        previousMillis = currentMillis;
        connectAndReadData();
      }
      break;
  }
  // Update Arduino IoT Cloud
  ArduinoCloud.update();
}