The tennis coach needs a better tennis ball serve for practice. This device must fire a sequence of standard tennis balls ball from one side of a standard tennis court over the net such that they land and bounce within each of three court areas defined by the court white lines. The order and frequency of the balls landing in any one of the three court areas must be random.
The device should operate automatically untended except for the refill of balls. It should fire 50 balls between reloads. The timing of ball release should vary. For simplicity a motor driven pin-jointed linkage design is preferred.