i'm measuring cars on race track using lasers + arduino. Setup is simple, on one end is laser, on another photo sensor with arduino, two in pair = working fine, i have speed of cars up to 300km/h. However i'm trying to find out how to make setup even simpler - to use laser as range finders so i will have just one box on one side of track. Basically i need fast range finder or some kind of obstacle detector. Right now i'm checking sensor status abour 600time per second, fastest laser finder for arduino i found is about 50x per second which is not enough.
Track is 3 - 4 meters wide, so i just need to find out if there is any obstacle (car) 2 meters from sensors as fast as possible.
I assume you can't have just one laser across the track (or across each lane) because the height varies... You are breaking a plane (not a line) with the forward-most part of the car, right? If the bumper height is a little higher or lower than the laser beam you speed reading is going to be low.
I think you can get 1mS resolution or better. That might mean modifying your sketch. You could probably use an interrupt. Or, you can make a "tight loop" where it's not doing anything except monitoring the input until it's triggered. Then, after it's triggered you can calculate & display the time and whatever else it needs to do.
