I need help Creating a small project for a friend of mine. By the Way my name is Ali and I am a fresh Graduate of a Bachelor degree in Computer Engineering.

I just need help to decide which sensors are the most precised to be used in this Car Race Project. By the way this is a real cars racing project.
I just made an image here to show how the rules and regulations of the race. or in other way, how the problem flow is.

The race will have only TWO CARS to race, I know this is a simple project for some of you; but i am not sure about what kind of sensor to use that can detect the car movement.
The race is a Time Lap Race, with only one Track for the same cars, it means that there is no over-taking from either cars, CAR1 or CAR2. The start line of CAR1 is other than the start line of CAR2, there will be a timer to detect the winner time (But don't care about it, I got this). lets say the race started, and of course they will run, when CAR1 passes through CAR2's Start line the timer will not yet stop (because it is only a half lap), same goes to CAR2 when reaches CAR1's Start line. when a Car Completes a LAP, the timer will stop there, either of the two cars, the timer will only stop when the sensor detects the car which left from its base (Start line) into the same line. I actually have the Idea how to know which car passes through, if it is CAR1 or CAR2, the problem is which sensor to be used to detect the car motion to stop the Timer from running. I had a problem in deciding sense I did not use any sensor that Can have a long range, and can sense exactly at a straight line, I already used a motion sensor but the one with an angle, maybe if I am not wrong it has a 90 Degree angle which can detect from 0 to 90 Degree, What I want is A SENSOR which can detect at a STRAIGHT Line, and can detect From a range of lets say 1 to 2 METERS. I hope some of the experts here can answer my Question. Please do help if you have an IDEA. Thank you So much.

 

You can use a laser pointer and a phototransistor. The laser will be a very focused beam and can be accurate - as long as nobody bumps it. Edit your post title to "race timer" so nobody confuses this with an automobile modification and locks your thread (car talk is verboten on this site).

 

Might review " Help with simple break beam switch" by deuce01, page 8 today. or put deuce01 in Find box, upper right this page.
How wide is the track?
Any headon crashes yet?

 

You can use a laser pointer and a phototransistor. The laser will be a very focused beam and can be accurate - as long as nobody bumps it. Edit your post title to "race timer" so nobody confuses this with an automobile modification and locks your thread (car talk is verboten on this site).

Honestly, I thought about it at first..I thought of using an Infrared boosted with a laser to have a strong sender of light, but I thought maybe it cannot have a strong range or not? I don't know, I was about to create a modified IR with the use of a laser. But I thought about it twice, and I said to myself maybe it would not be possible. Can it be? Can the reflection (when the car passes through) be bounced back to the Infrared Receiver?

Sorry But I can't Find the edit Button of the Thread.

 

other thing I thought about is using RFID to detect the cars passing through, but again, Long Range RFID's is a lot expensive.

 

Why do you need a sensor range of 1 to 2 metres? That is causing all your problems!

If you can change the design slightly and put the sensors on the track or very close to the track it will become very easy.

 

Why do you need a sensor range of 1 to 2 metres? That is causing all your problems!

If you can change the design slightly and put the sensors on the track or very close to the track it will become very easy.

What do you mean by ON THE TRACK? like on the ground or something?

it is a real race with real cars, the sensor maybe will be damaged if it is like that. it should be on the sides or something.

 

A "real race" would never be run with two cars on the same track, because the winning car would smash into the back of the slower car. A proper racetrack would always have two separate tracks, likely in a figure-8 to make sure both track distances are the same.

And by "on the track" I meant NOT two metres away! That could mean mounted a couple of inches from the track and cars, or as a bridge over the track, or even under the track sensing the cars moving over the top.

Please have a google for "slot car racing tracks" and "clubs" and see some of the standard ways they set up lap sensors on the tracks.