I want to compute the compass' direction, so I use the following code:
SensorManager mManager = (SensorManager)mContext.getSystemService(Context.SENSOR_SERVICE);
Sensor accelerometer = mManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
Sensor magnetometer = mManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
mManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
mManager.registerListener(this, magnetometer, SensorManager.SENSOR_DELAY_NORMAL);
private float mR[] = new float[9];
private float mI[] = new float[9];
float mOrientation[] = new float[3];
....
public void onSensorChanged(SensorEvent event)
{
if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER)
mGravity = event.values;
if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD)
mGeomagnetic = event.values;
if (mGravity != null && mGeomagnetic != null) {
boolean success = SensorManager.getRotationMatrix(mR, mI, mGravity, mGeomagnetic);
if (success) {
SensorManager.getOrientation(mR, mOrientation);
int azimut = (int) (mOrientation[0]*180/3.14159f); // This is the data
}
}
}
It usually works fine. It does not work when there is an interference with the magnetic field - for example under my car radio. In that case - I get a wrong constant reading.
how can I detect magnetic interference?
