Abstract: Systems are disclosed for making automated decisions in tennis based on analyzing effects resulting from the bounce of a tennis ball by means of pattern recognition in order to determine whether the detected "bounce" was a valid bounce of a tennis ball and not caused by other events. The tennis court is laid out with electrical circuits which can define "in" and "out" areas of the court. These circuits are connectable to a network of micro-computers which can analyze the makes and breaks in the electrical circuits resulting from the bounce of an electrically conductive tennis ball and compare said results with predetermined patterns of makes and breaks caused by known valid ball bounces. The systems are designed on a flexible basis to operate with or without an umpire.The systems use an electrically conductive tennis ball which makes and breaks electrical circuits when bouncing on them.