My students are building a co2 dragster timer with an arduino and some hardware and lcd screen. Right now, we are using a laser pointer aimed at a photo resistor and when the beam is broken it starts the timer and same thing to stop the timer 50 feet away. The problem we experience is the reaction time of our system is two slow for the fast moving co2 cars. If we break the beam with our hand slowly it works fine but not quite good enough. The question is, what kind of sensor would be the best for sensing rapidly moving objects with a school budget in mind.
Tahnks
