Building a sensor chronograph to measure speed of batted ball

I need a sensor chronograph designed to measure the speed of a batted baseball. It would consist of a frame assembly mounted on a pole in front of home plate in a batting cage. The goal would be for the device to be stationary, able to measure the speed of a batted ball on demand and then displaying it on an LCD positioned 30-60 feet away. It should be automatic and unattended, working without anyone doing anything to activate it other than hitting an oncoming pitch. We are interested in measuring only the batted ball, not the pitched ball from the pitcher or the swing speed of the bat.

The measuring area would need to be about 2-6 feet high (depending on how far in front of home plate it is positioned) to accommodate a batted ball that is hit high or low. It should be able to measure the speed of any ball hit fair, from the first base line to the third base line.  The speed of the batted ball would range anywhere from 40 to 130 mph. Since the device would be used on a repetitive, long term basis care would need to be taken during the design to provide for protection from any batted balls that might find their way into the device itself (a piece of screen, chain link or plexiglass installed in front of it?)

If you know where I might obtain a working apparatus or might locate someone willing to build one I would appreciate your response to the email address below.

Jerry Heath