I have a little experiece with Visual Basic 3.0, but I have not written code in quite a while.  I would like to write a stop watch program that would get inputs from external photoelectric sensors.  The sensors will be placed 200 feet apart on a pond to measure top speeds of radio controlled boats.  Is this possible?  Would there be any other hardware needed to link the photoelectric sensors to the computer?  I assume there might be a piece of hardware that plugs into a USB port and then the sensors can be linked up? 

Thanks for any help.