AUTOMATIC PROGRAMMABLE TENNIS-BALL SERVING DEVICE CONTROLLED BY MICROCOMPUTER

A new ball throwing machine for ejecting tennis balls comprising an adjustable ball throwing mechanism, a microcomputer controlling the throwing mechanism for programmed stroke sequences, and a remote control unit attached to the microcomputer and having a touch pad keyboard for direct assignment of impact points of the balls and for command selection and, for balls impacting on a center line of a tennis court, the throwing mechanism is controlled for determining a vertical angle and a launching speed of throwing out the balls on basis of linear interpolation between co-ordinates of two check points of the impact of balls, of a training level and a stroke type preselected on the keyboard, and the first check point is a meshing point of a net and the center line of the tennis court, the second check point is a meshing point of a baseline and the center line; for all other balls, also a horizontal angle of throwing out the balls is determined by a simple trigonometric relation, and a memory is provided in the microcomputer for storing the angle and speed data of each impact point.