Android Xoom Accelerometer Accuracy Always Reliable

Question

I am working on a simple compass type app for Android, testing Xoom WiFi. The accuracy of the accelerometer readings is always SensorManager.SENSOR_STATUS_UNRELIABLE . Magnetic field readings are always the accuracy of the SensorManager.SENSOR_STATUS_ACCURACY_HIGH . Could this be a bug in Xoom, or is there a problem in my code?

 onCreate: mSensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE); accelGravitySensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); magSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD); onResume: mSensorManager.registerListener(accelListener, accelGravitySensor, SensorManager.SENSOR_DELAY_NORMAL); mSensorManager.registerListener(magListener, magSensor, SensorManager.SENSOR_DELAY_NORMAL); private final SensorEventListener accelListener = new SensorEventListener() { public void onSensorChanged(SensorEvent event) { Log.d(TAG, "accel (" + event.values[0] + ", " + event.values[1] + ", " + event.values[2] + ") accuracy=" + accuracyTag(event.accuracy)); } public void onAccuracyChanged(Sensor sensor, int accuracy) {} }; 

Answer 1

Sounds like a bug in xoom. Check out these posts:

http://community.developer.motorola.com/t5/Android-App-Development-for/Xoom-magnetometer-Y-axis-always-reads-zero/td-p/14184

http://community.developer.motorola.com/t5/Android-App-Development-for/Q-Compass-Behavior-when-Xoom-is-held-in-different-orientations/td-p/14332

Answer 2

Nexus S also has this problem (with a gyroscope), and it looks like the lazy driver writer forgot to set the reading accuracy field;)

As long as the data is beautiful, it should be purely cosmetic.

Answer 3

I don’t know if you have problems with the accuracy of the compass, but I know what I did when I used

 magSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD) 

I highly recommend using something more like the following.

  mySensorManager = (SensorManager)getSystemService(Context.SENSOR_SERVICE); List<Sensor> mySensors = mySensorManager.getSensorList(Sensor.TYPE_ORIENTATION); if(mySensors.size() > 0){ mySensorManager.registerListener(mySensorEventListener, mySensors.get(0), SensorManager.SENSOR_DELAY_NORMAL); sersorrunning = true; Toast.makeText(this, "Start ORIENTATION Sensor", Toast.LENGTH_LONG).show(); } 

I found that when I used a magnetic field sensor rather than an orientation sensor, it worked very well on my phone (Droid Incredible), but all kinds of crazy things on my wife’s phone (Droid Pro) and my colleague’s phone (Samsung Galaxy Tab). So you might consider replacing the sensor, just for device compatibility issues. :-)