thank you all, I must have had IR on the brain, yes reed switches and tactiles on a lever sound like a very good idea, i was trying to work out a way of using the usual lap counter to make a signal but figured that the adaption was going to be more complicated than a from scratch thing.
Luckily I have some hitachi driven 16x2 displays and the arduino has a library for them so in theory I might even be able to cobble something together in a couple of weeks, having learnt to use interupts
I've never used reeds before, anything I should know ?