For instance, let's consider the simple and low cost OM02 . The sensor measures position by acquiring surface image frames and mathematically determining the movement direction and value. The sensor is mounted in a polystyrene optical package and is designed to be used with a high intensity LED. It provides a complete and compact tracking engine. It has no moving parts and requires no precise optical alignment. The OM02 produces a quadrature output for both X and Y directions of movement. The resolution is about 0.0025 inches, and the motion speed, up to 16 inches per second.