Racing Time and Time Logs

So, I'm helping out with a pinewood derby race and our plan for using some expensive race timing equipment went south. Instead of eyeballing the races I was thinking of using the arduino but I have only the requirements that need to be met.

  • start timing as the manual release is set off
    I was thinking of using a type of break connection switch using two plates of metal that will come apart as the release falls
  • stop times with cars trip the laser
    There are tutorials in several places, I should be fine here
  • display times
    I have figured whether what would be the best method yet
  • log time to a file for disputes
    I'm looking up tutorials on how to store data so hopefully I'll be fine here.

I guess what I'm really looking for here is guidance from those that have done things like this. Any constructive help is welcomed

A part of the sketch might be my Stopwatch class which supports lap times - called value() - and can be instantiated multiple times.
See - Arduino Playground - StopWatchClass - for details