Adnroid using Accelerometer

public class Main extends Activity implements SensorEventListener {
    private SensorManager senSensorManager;
    private Sensor senAccelerometer;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        senSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        senAccelerometer = senSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        senSensorManager.registerListener(this, senAccelerometer , SensorManager.SENSOR_DELAY_NORMAL);
    }
 
    @Override
    public void onSensorChanged(SensorEvent sensorEvent) {
        Sensor mySensor = sensorEvent.sensor;
 
        if (mySensor.getType() == Sensor.TYPE_ACCELEROMETER) {
            float x = sensorEvent.values[0];
            float y = sensorEvent.values[1];
            float z = sensorEvent.values[2];
     
            long curTime = System.currentTimeMillis();
     
            if ((curTime - lastUpdate) > 100) {
                long diffTime = (curTime - lastUpdate);
                lastUpdate = curTime;
     
                float speed = Math.abs(x + y + z - last_x - last_y - last_z)/ diffTime * 10000;
     
                if (speed > SHAKE_THRESHOLD) {
     
                }
     
                last_x = x;
                last_y = y;
                last_z = z;
            }
        }
    }
}