miscale test

/**
 * An ESP32 BLE client to retrieve data from the Weight Measurement characteristic
 * of a Xiaomi Mi Smart weight scale
 * Author Pangodream
 * Date 2020.05.31
 */
#include "BLEDevice.h"
//Base UUIDs
//Weight Scale service
static BLEUUID srvUUID("0000181d-0000-1000-8000-00805f9b34fb");
//Weight Measurement characteristic
static BLEUUID chrUUID("00002a9d-0000-1000-8000-00805f9b34fb");
static BLEAdvertisedDevice* scale;
static BLERemoteCharacteristic* remoteChr;
static boolean doConnect = false;
static boolean connected = false;
static int year = 0;
/**
 * Callback function for characteristic notify / indication
 */
static void chrCB(BLERemoteCharacteristic* remoteChr, uint8_t* pData, size_t length, bool isNotify) {
    //Console debugging
    Serial.print("Received data. Length = ");
    Serial.print(length);
    Serial.print(". - Data bytes: ");
    for(int i =0; i< length; i++){
      Serial.print(pData[i]);
      Serial.print("  ");
    }
    Serial.println(" ");
    //End of console debugging

    //Parsing the received data and calculate weight
    boolean temporary = true;
    int rcvdYear = pData[3];
    //If we received a year for the first time, store it in the year variable
    //The first year we receive indicates a temporary measurement
    if(year == 0){
      year = rcvdYear;
    }else{
      //If year has been previously defined and the year we have received is
      //greater than it, then the measurement is not temporary, is the final one
      if(rcvdYear > year){
        temporary = false;
      }
    }
    double weight = 0;
    weight = (pData[1] + pData[2] * 256) * 0.005;

    Serial.print("Weight: ");
    Serial.print(weight);
    Serial.print(" Kg - ");
    if(temporary){
      Serial.println(" (Provisional)");
    }else{
      Serial.println(" (Definitive)");
    }
}
/**
 * Callback class for each advertised device during scan
 */
class deviceCB: public BLEAdvertisedDeviceCallbacks {
 //Called on each advertised device
  void onResult(BLEAdvertisedDevice advertisedDevice) {
    // We have found a device, let us now see if it contains the service we are looking for.
    if (advertisedDevice.haveServiceUUID() && advertisedDevice.isAdvertisingService(srvUUID)) {
      if(advertisedDevice.getName() != "MI_SCALE"){
        Serial.print(".");
      } else {
        Serial.println("  Found!");
        BLEDevice::getScan()->stop();
        Serial.println("Stopping scan and connecting to scale");
        scale = new BLEAdvertisedDevice(advertisedDevice);
        doConnect = true;
      }
    } else {
      Serial.print(".");
    }
  }
};
/**
 * Callback class for device events
 */
class ClientCB : public BLEClientCallbacks {
  void onConnect(BLEClient* pclient) {
  }
  void onDisconnect(BLEClient* pclient) {
    Serial.println("Disconnected. Reconnecting...");
    connected = false;
  }
};
bool connectToScale() {
    Serial.println("Stablishing communications with scale:");
    BLEClient*  pClient  = BLEDevice::createClient();
    Serial.println("    BLE client created");
    pClient->setClientCallbacks(new ClientCB());
    // Connect to the remove BLE Server.
    pClient->connect(scale);
    Serial.println("    Connected to scale");
    // Obtain a reference to the service we are after in the remote BLE server.
    BLERemoteService* pRemoteService = pClient->getService(srvUUID);
    if (pRemoteService == nullptr) {
      Serial.println("    Error: Failed to find service");
      pClient->disconnect();
      return false;
    }
    Serial.println("    Service found");
    remoteChr = pRemoteService->getCharacteristic(chrUUID);
    if (remoteChr == nullptr) {
      Serial.print("    Failed to find characteristic");
      pClient->disconnect();
      return false;
    }
    Serial.println("    Characteristic found");
    Serial.println("    Setting callback for notify / indicate");
    remoteChr->registerForNotify(chrCB);
    return true;
}
void setup() {
  Serial.begin(115200);
  Serial.println("Searching for MI_SCALE device");
  BLEDevice::init("");
  BLEScan* pBLEScan = BLEDevice::getScan();
  pBLEScan->setAdvertisedDeviceCallbacks(new deviceCB());
  pBLEScan->setInterval(1349);
  pBLEScan->setWindow(449);
  //Set active scan
  pBLEScan->setActiveScan(true);
  //Scan during 5 seconds
  pBLEScan->start(5, false);
}
void loop() {
  if(doConnect && !connected){
    connected = connectToScale();
  }
  delay(1000);
}