number goes second time less then 100

i am using the orientation sensor in the android app. I want to find out when the sensor value goes less than 100 second time. how to find it.

        public void onSensorChanged(SensorEvent event) {
        // TODO Auto-generated method stub
          if( event.sensor.getType() == Sensor.TYPE_ORIENTATION)
             {
              value= (event.values[0]);


     if (value<100){

        }
          }}