Detect Movement Accurately using Accelerometer in Android

Question

I am implementing a demo TIMER, with Vibration ( at a particular condition ), When I press start my timer starts running.. and when I stop it using stop button, it simply stops.

Answer 1

To find linear acceleration in a particular direction you can use this code too:

    @Override
public void onSensorChanged(SensorEvent event) {
// alpha is calculated as t / (t + dT)
// with t, the low-pass filter's time-constant
// and dT, the event delivery rate

final float alpha = 0.8f;

gravity[0] = alpha * gravity[0] + (1 - alpha) * event.values[0];
gravity[1] = alpha * gravity[1] + (1 - alpha) * event.values[1];
gravity[2] = alpha * gravity[2] + (1 - alpha) * event.values[2];

linear_acceleration[0] = event.values[0] - gravity[0];
linear_acceleration[1] = event.values[1] - gravity[1];
linear_acceleration[2] = event.values[2] - gravity[2];
}  

after calculating the linear acceleration you can simply use an 'if' statement to check whether you jerk was powerful or not! [Higher value= more powerful jerk]