Ok, so instead of forking out big bucks ($600 or so) for one of these: http://www.aimsports.com/products/tg/index.html I have gone the cheapo route and decided to build my own. Sofar im using a cheap DSE stopwatch with lap function: http://dseau.resultspage.com/search...13bed82743c0a87f9c0723&method=and&isort=score And an Infrared detector from Jaycar: http://www.jaycar.com.au/productVie...d2=&pageNumber=&priceMin=&priceMax=&SUBCATID= And ill connect the two together with a relay so that the IR detector can trip the lap "button" on the stopwatch. However, my issue isnt so much with the triggering but the fact that on any given track day there are normally 5-10 people out with laptimers and each will have their own IR beacon down the pit straight. The way it will be connected now the IR detector will trip the lap button multiple times when i drive down pit straight, which obviously isnt what i want. What i want to do is create a small delay circuit for the signal from the IR detector to the relay. I had first thought of using a 555 timer in a monostable trigger, but thatll mean fabbing up a breadboard etc to set it up. So can anyone think of a simpler way of doing this?