QMC5883 magnetometer

// NOTE TESTET BEHIND MPU6050


/*!
 * @file QMC5883_compass.cpp
 * @brief The program shows how to realize the function compass.When the program runs, please spin QMC5883 freely to accomplish calibration.
 * @n 3-Axis Digital Compass IC
 *
 * @copyright	[DFRobot](http://www.dfrobot.com), 2017
 * @copyright	GNU Lesser General Public License
 *
 * @author [dexian.huang](952838602@qq.com)
 * @version  V1.0
 * @date  2017-7-3
 */

#include <Wire.h>
#include <DFRobot_QMC5883.h>
#include <MPU6050.h>

MPU6050 mpu;
DFRobot_QMC5883 compass;

void setup()
{
  Serial.begin(115200);

  Wire.begin();
   mpu.initialize();
  mpu.setI2CBypassEnabled(true);
  delay(200);
  while (!compass.begin())
  {
    Serial.println("Could not find a valid QMC5883 sensor, check wiring!");
    delay(500);
  }

    if(compass.isHMC()){
        Serial.println("Initialize HMC5883");
        compass.setRange(HMC5883L_RANGE_1_3GA);
        compass.setMeasurementMode(HMC5883L_CONTINOUS);
        compass.setDataRate(HMC5883L_DATARATE_15HZ);
        compass.setSamples(HMC5883L_SAMPLES_8);
    }
   else if(compass.isQMC()){
        Serial.println("Initialize QMC5883");
        compass.setRange(QMC5883_RANGE_2GA);
        compass.setMeasurementMode(QMC5883_CONTINOUS);
        compass.setDataRate(QMC5883_DATARATE_50HZ);
        compass.setSamples(QMC5883_SAMPLES_8);
   }
  }
void loop()
{
  Vector norm = compass.readNormalize();

  // Calculate heading
  float heading = atan2(norm.YAxis, norm.XAxis);

  // Set declination angle on your location and fix heading
  // You can find your declination on: http://magnetic-declination.com/
  // (+) Positive or (-) for negative
  // For Bytom / Poland declination angle is 4'26E (positive)
  // Formula: (deg + (min / 60.0)) / (180 / M_PI);
  float declinationAngle = (4.0 + (26.0 / 60.0)) / (180 / PI);
  heading += declinationAngle;

  // Correct for heading < 0deg and heading > 360deg
  if (heading < 0){
    heading += 2 * PI;
  }

  if (heading > 2 * PI){
    heading -= 2 * PI;
  }

  // Convert to degrees
  float headingDegrees = heading * 180/M_PI;

  // Output
  Serial.print(" Heading = ");
  Serial.print(heading);
  Serial.print(" Degress = ");
  Serial.print(headingDegrees);
  Serial.println();

  delay(100);
}