The batter monitoring system is a modified home plate for baseball including a sensor unit to detect whether or not the bat crosses the plate as a hitter swings at a pitched ball and also when a runner crosses the plate. After the pitch, a green light is illuminated to indicate that the batter swung...http://www.google.co.uk/patents/US7270616?utm_source=gb-gplus-sharePatent US7270616 - Batter monitoring system
