System for detecting foot faults in ball game, e.g. ten pin bowling, uses laser light beam and is simple, compact and robust

摘要

The system is connected to a computer which takes the appropriate action if a player's foot goes over a line and 'breaks' a beam of visible or invisible light is generated by a laser element (2) . The beam is reflected (5) back across the alley and passes through the rod of transparent plastic (14) which surrounds the laser (2). The reflected light (7) is focused onto a detector (4) behind the laser by the focusing element (3) of the rod.