Computer 'shot clock' or timer wanted for sport?

I am trying to find a computer program that will time shots for goalball which is a sport for vision impaired people. What I want is one that will time for 10 seconds and you can stop one count and start the next with the hitting of one key. With a stopwatch you have to press keys 3 times in order and it is easy to make a mistake.

Also there needs to be a seperate pause key.

If the clock could also count up or down to 45 seconds and 3 minutes for time outs and half time break, that would be even better.

If you know of something like this available or could write the program that would be great.