Experimental code to acquire data from SwitchBot Thermometer/Hygrometer by M5Stack.

M5-SwitchBotTH.ino

#include <M5Stack.h>
#include <BLEDevice.h>

static BLEUUID SWITCHBOT_ServiceDataUUID( "0000fd3d-0000-1000-8000-00805f9b34fb" );
#define SWITCHBOT_CompanyID    0x0969
#define SWITCHBOT_DeviceType   'T'

class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks {
  void onResult(BLEAdvertisedDevice advertisedDevice) {
    Serial.print("BLE Advertised Device found: ");
    Serial.println(advertisedDevice.toString().c_str());

    bool CompanyID_match = false;
    if ( advertisedDevice.haveManufacturerData() ) {
      std::string data = advertisedDevice.getManufacturerData();
      if ( data.length() >= 2 ) {
        uint16_t CompanyID = data[0] | ( (uint16_t)data[1] << 8 );
        if ( CompanyID == SWITCHBOT_CompanyID ) {
          CompanyID_match = true;
        }
      }
    }

    std::string ServiceData;
    bool ServiceDataUUID_match = false;
    if ( advertisedDevice.haveServiceData() ) {
      ServiceData = advertisedDevice.getServiceData();
      if ( advertisedDevice.getServiceDataUUID().equals( SWITCHBOT_ServiceDataUUID ) ) {
        ServiceDataUUID_match = true;
      }
    }

    bool DeviceType_match = false;
    if ( ServiceDataUUID_match ) {
      if ( ServiceData[0] == SWITCHBOT_DeviceType ) {
        DeviceType_match = true;
      }
    }

    if ( CompanyID_match && ServiceDataUUID_match && DeviceType_match ) {
      uint8_t battery = ServiceData[2] & 0x7f;
      float temperature = ( ServiceData[4] & 0x7f ) + ( ServiceData[3] & 0x0f ) * 0.1F;
      if ( ( ServiceData[4] & 0x80 ) == 0 ) {
        temperature = -temperature;
      }
      uint8_t humidity = ServiceData[5] & 0x7f;

      Serial.println( "Found a meter!" );
      BLEDevice::getScan()->stop();

      M5.Lcd.println( "Found a meter!" );
      M5.Lcd.print( "MAC:  " );
      M5.Lcd.println( advertisedDevice.getAddress().toString().c_str() );
      M5.Lcd.print( "Temp: " );
      M5.Lcd.println( temperature );
      M5.Lcd.print( "Hum:  " );
      M5.Lcd.println( humidity );
      M5.Lcd.print( "Batt: " );
      M5.Lcd.println( battery );
    }
  }
};

void setup() {
  Serial.begin( 115200 );
  M5.begin();
  M5.Lcd.setTextSize( 2 );

  M5.Lcd.println( "BLE scan start." );
  BLEDevice::init( "" );
  BLEScan* pBLEScan = BLEDevice::getScan();
  pBLEScan->setAdvertisedDeviceCallbacks( new MyAdvertisedDeviceCallbacks( ));
  pBLEScan->setInterval( 510 );
  pBLEScan->setWindow( 449 );
  pBLEScan->setActiveScan( true );
  pBLEScan->start( 5, false );
}

void loop() {
  delay( 1000 );
}