What I would like to make is a circuit that will time a car going down a pine wood derby track. What I was thinking is a micro-switch that will start the circuit and the timer when the car leaves the starting post and then stops the clock when the car finishs the track. I would like the stopper to be a sensor that registers when the car is under it. I'm just not sure where I should start. Sorry if it doesn't make a whole lot of sense just can't seem to think straight tonite.