SW-520D Roller Ball Tilt Switch, brass case sealed in Shrink Tubing to avoid short circuits. When the sensor is oriented so the leads are downwards, the mass rolls onto the poles and shorts them, acting as a throw switch. While not as precise or flexible as a a full accelerometer, roller ball tilt switches can detect motion or orientation simply. Accelerometers, on the other hand, output digital or analog voltage that must then be analyzed with extra circuitry. Characteristics: