I tried some searching here and google but came up with no results, probably for a reason, but I'll ask anyways...

Has anyone tried to make a DIY lap counter/timer for 1 car for practicing? I was thinking possibly using one of the motion detectors that use the laser beams you can buy at HomeDepot and somehow (electrical people needed here) wire it up to hook up to a PC or laptop. From there (assuming that is possible) I don't think it would be too hard to write a little VBA script to keep track of laps and times in Excel.

Doable, has it been done, or am I nuts?