Shake detection counter

Question

Is there a simple way to detect a shake, if there are multiple shakes one after the other then set a counter and when the counter has reached a limit then it stops counting?

Answer 1

From the code point of view, you need to implement the SensorListener:

public class ShakeActivity extends Activity implements SensorListener

You will need to acquire a SensorManager:

sensorMgr = (SensorManager) getSystemService(SENSOR_SERVICE);

And register this sensor with desired flags:

ensorMgr.registerListener(this,
SensorManager.SENSOR_ACCELEROMETER,
SensorManager.SENSOR_DELAY_GAME);

In your onSensorChange() method, you determine whether it’s a shake or not:

public void onSensorChanged(int sensor, float[] values) {
  if (sensor == SensorManager.SENSOR_ACCELEROMETER) {
    long curTime = System.currentTimeMillis();
    // only allow one update every 100ms.
    if ((curTime - lastUpdate) > 100) {
      long diffTime = (curTime - lastUpdate);
      lastUpdate = curTime;

      x = values[SensorManager.DATA_X];
      y = values[SensorManager.DATA_Y];
      z = values[SensorManager.DATA_Z];

      float speed = Math.abs(x+y+z – last_x – last_y – last_z) / diffTime * 10000;

      if (speed > SHAKE_THRESHOLD) {
        Log.d("sensor", "shake detected w/ speed: " + speed);
        Toast.makeText(this, "shake detected w/ speed: " + speed, Toast.LENGTH_SHORT).show();
      }
      last_x = x;
      last_y = y;
      last_z = z;
    }
  }
}

The shake threshold is defined as:

private static final int SHAKE_THRESHOLD = 800;

There are some other methods too, to detect shake motion. look at this link.(If that link does not work or link is dead, look at this web archive.).

Thanks.

Answer 2

You can Implement the SensorManager class.

Check answers and links Here.