code: private static int processVelocity(VERTICAL_DIRECTION direction, float sensorReading, float maxSensorReading) {
  
  		switch (direction) {
  
  			case UP: return (int) (-1 * (maxSensorReading + sensorReading));
  	
  			case DOWN: return (int) sensorReading;
  	
  			case NONE: default: return 0;
  		}
  	}
docs: <p>Takes the motion sensor reading on the Y-Axis and converts it to
  a vector with a direction which is essentially the <b>velocity</b>.
  
  @param direction
  the {@link VERTICAL_DIRECTION} of the motion
  
  @param sensorReading
  the sensor reading on the Y-Axis
  
  @param maxSensorReading
  the maximum value which can be reached by a sensor reading
  
  @return the processed Y-Axis velocity