Need Help: Sensor to be used in Car Racing Project

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.

So, if I understand what you are asking, you need something to detect when one or the other cars pass the finish line (which is the same as the starting line, two passes around the track later).

So, how about a simple "electric eye" -- basically a beam of light (could be infrared [IR] or visible light). There are two basic arrangements:
1. The beam sender is on one side of the car and the receiver (or beam detector) is on the other side. The drawback is that a wire needs to be run back to the sender.
2. The beam sender and the receiver are on the same side. On the other side is a reflector that reflects the beam back to the receiver. The best kind of reflector for this is a retroreflector (i.e. like a bicycle reflector).

If you modulate the beam it becomes less vulnerable to stray light -- if stray light swamps the receiver, it can raise an alarm.

This sort of beam system is used:

1. to detect people walking through a door, like in a bakery to ring a bell.
2. in alarm systems


Other possibilities:

* pneumatic switch, like in gas stations back when they were _full serve_ -- basically a rubber tube closed at one end and connected to a pressure switch at the other end.
* metal detector, like that used at traffic light intersections or on freeways to measure the flow rate of traffic.
* video camera connected to motion detection equipment -- used in security systems.
* RFID on the car with RFID reader at the finish line -- this could also be used to distinguish between the cars (not sure, though, if there would be enough range).

RFID sounds like the best answer OR Steve Bar code reader on each car Different bar code on each one , unique identifier

Doesn’t matter then if its on the same side of each car ( that’s by far the best idea even better than RFID ) you will get a slight time delay maybe 0.004micro seconds error per line of the bar code Of course that would depend on instruction time


What do you reckon on that one then ? Not bad huh !! For the el thicko dimwit like me is it ? Still not to worry cant spell but I can solve problems and program quite well , find faults and when asked design and biuld what they want Or what some people decsribe as the ee aw ee aw eeaw "Donkey in other words "Lovley isnt it !! " so long as we have someone to do the Donkey work for them then its ok

It pays to learn how to put a database together doesn’t it! it also pays to work on a shop floor even if it is packing shelves strange how you can think a little further and apply this to racing car tracks and embedded technology

Just shows you that anyone who works on a shop floor just by doing something as simple as packing shelves can learn stack architecture, bar car reading stock control and finally work out how to apply this somewhat boring task to something far more advanced and then later use this to solve a seemingly daunting problem

Dont have to be the brains of britain do you to work some of this out

Funny this I was just thinking tonight as I’m working through access database which I’m writing at the moment how I could implement a bar code reader to scan my invoices and bill to customers so we don’t get typing errors or as we say Human error !! Weird how Science works don’t you think? Take practical environment and apply this laterally to a problem

The next use for RFID is dodgy taxt disks then you all you have to do is take your reader up to the vehicle reads it through the glass windows and youve solved that problem as well , quote, "We dont want you thinking " and quote " Ypur a bit to clever for your own good " Unquote ..... Good memory as well very good Just like those african elephants

You haven’t seen those African elephants when they go on the rampage have you " They've got sex organs on there feet you know Dont believe me do you They have too , my tosies they call them huge great big feet , massive enormous feet , possibly spelt mitosis , "Cell division " Especially when they stamp on you terrible pain they can inflict ,awful pain

Leaves many people paralyzed , unable to walk for months

Not sure if a bar code could be read fast enough [as the car is speeding past].

Another thought for you You could use a similar mechanism that they use on railway lines when a train passes over a signal box the signal box pics up a trigger from the train this records the time then after which this then sends a msg to the train telling it to transmit its ID

ID logged with time time being logged first followed by ID

http://www.railway-technical.com/sigtxt5.shtml

http://cs.swan.ac.uk/~csal/Talks/Railwaytalk1.pdf

ATP Speed Codes

A train on a line with a modern version of ATP needs two pieces of information about the state of the line ahead - what speed can it do in this block and what speed must it be doing by the time it enters the next block. This speed data is picked up by antennae on the train. The data is coded by the electronic equipment controlling the track circuitry and transmitted from the rails. The code data consists of two parts, the authorised speed code for this block and the target speed code for the next block. The diagram below shows how this works.

ATP system In this example (left), a train in Block A5 approaching Signal A4 will receive a 40 over 40 code (40/40) to indicate a permitted speed of 40 km/h in this block and a target speed of 40 km/h for the next. This is the normal speed data. However, when it enters Block A4, the code will change to 40/25 because the target speed must be 25 km/h when the train enters the next Block A3. When the train enters Block A3, the code changes again to 25/0 because the next block (A2) is the overlap block and is forbidden territory, so the speed must be zero by the time train reaches the end of Block A3. If the train attempts to enter Block A2, the on-board equipment will detect the zero speed code (0/0) and will cause an emergency brake application. As mentioned above, Block A2 is acting as the overlap or safe braking distance behind the train occupying Block A1.
Operating with ATP

Trains operating over a line equipped with ATP can be manually or automatically driven. To allow manual driving, the ATP codes are displayed to the driver on a panel in his cab. In our example below, he would begin braking somewhere around the brake initiation point because he would see the 40/25 code on his display and would know, from his knowledge of the line, where he will have to stop. If signals are not provided, the signal positions will normally be indicated by trackside block marker boards to show drivers the entrances to blocks.

ATP system If the train is installed with automatic driving (ATO - Automatic Train Operation), brake initiation for the reduced target speed can be by either a track mounted electronic "patch" or "beacon" placed at the brake initiation point or, more simply, by the change in the coded track circuit. Both systems are used by different manufacturers but, in both, the train passes through a series of "speed steps" to the signalled stop.

When the first train clears Block A1, the codes in Blocks A2, A3 and A4 will change to the next speed up and any train passing through them will receive immediately a new permitted speed and a new target speed for the next block. This allows an instant response to changing conditions and helps to keep trains moving.

http://www.railway-technical.com/sigtxt2.shtml

...

Actually, for that to work, the cars would have to have steel wheels.

Whoops -- didn't read the whole post -- guess this is a system that I don't know about.

...or I may be correct:

"Electric track circuits enabled the detection of trains automatically." -- _Railwaytalk1.pdf_

Here in the USA this is done by using the rails as a switch. When the steel wheels roll onto the electrified rails, the wheels and axle complete the circuit, much like a switch closing. I once tested this with a set of jumper cables. I shorted across the rails and the signal light started flashing and the gate began to lower! That was around 30 years ago, so if there is a law against doing that, hopefully I'm beyond the statute of limitations ;)

* http://signaldepartment.com/articles/xing-dc/default.html
* http://www.uprr.com/she/safety/xing_safety/sentinels.shtml
* http://safety.fhwa.dot.gov/xings/com_roaduser/07010/sec04b.htm [scroll down to *16. Train Detection*]

I think this is almost the same as what I thought about..At first I thought about using a Modified IR, what I mean is to use a strong beam of light (Like, Laser) and then put then on the same side like your #2 arrangement (But without the reflector). Then I thought about it once, and twice, and I said to myself "Maybe it would not give a drawback reflection because of the range of the IR." But I am not sure if it will work, I thought that there are other ready to use long range sensors. That's why I asked.

But what is the use of the reflector? the car maybe can reflect the light when it passes through right?

RFID Sounds nice as it also can detect which car has passed by, I also thought about it but Almost all of the RFID's I used is a short range, I used the RDM630 which ranges from 5 to 10cm only. Are there cheap long range RFID Receivers?

Good point -- the car might, indeed, reflect the beam back to the receiver.

* http://www.iautomate.com/products/rfid-development-kit-great-for-proof-of-concept.html

But, now that I think about it, there may not be a consistent point of detection. In other words, the distance from the receiver to the car at the moment that the RFID tag is read may not always be the same -- which could be a problem if precise determination of the time of arrival to the finish line is important.

I think a laser beam across the track is the best bet. Or the induction coil ("metal detector"), but the car would need to consistently run directly over the coil to produce a repeatable result.