RC car time measurement

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#1
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Hi
I'm thinking about building a rc car track, but i would like to have a timing system that could print out the lap times for each car. The problem i find the most difficult is to tell each car from the other since there are not going to be any separated lanes.
Any suggestions on how to do it?

Thanks

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Each car could have an IR LED modulated at a certain frequency pointed in such a way that a detector tuned for that frequency could see the LED as the car passed. You would of course have to have a detector for each frequency, and it would be up to you to come up with a creative way of ensuring that the IR light can always be seen by a detector. It should work though...

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Consider barcode on the bottom of each car?

You would need to have several sensors looking upwards, spaced so that a car can't pass unnoticed. User Project 96 has the software - I would guess that you would want to port it to ATTiny because you'll need quite a few. As written, it's just under 2K, but you won't need all of that to tell a few cars apart.

I think that a sensor design will be the hardest part. Unfortunately Project 96 assumes that you already have a conditioned TTL signal from a barcode pen. I would use really fat bars so the resolution doesn't have to be really good, and start with a reflective sensor and try different lenses.

Example: If the cars are 5 inches wide, then you can hopefully find a flat area 1" by 3" just forward of the front suspension. The sensors could be 2" apart under the track; a 16" wide track would need about 8 of them.

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Lake Whipporwilll International Speedway in Narcoosee Florida was using RF tags at the RC meets way back ten years or so ago. Every car got a chip or something to put in the car, and it was all electronic lap time, etc. Bet this is standard procedure at the pro RC meets. Same at the local track meets... everybody gets a bug to tie on their showlaces.....

Imagecraft compiler user

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Texas Instruments sells RFID evaluation kits for $250 upwards....

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SteveN wrote:
Hi,

ezcomp wrote:

Quote:
You would of course have to have a detector for each frequency

Why not have each car transmit the equivalent of a button push on a IR TV/VCR/DVD remote. Each car would be the equivalent of a different button push. I am not familiar with these RC cars so I have no idea what sort of space is available for the circuit and battery. The transmit and receive code and circuits are already available.

The one problem I can think of is how ambient light might affect the reception.

Regards,
Steve


This is a much better idea! Don't know why I didnt think of it .... :wink:

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A problem with anything active on the car is that it needs to be small and light. Racers in particular are going to be pretty wary of adding weight to their cars, even a few grams (unless we're talking about 1/5 scale here). :shock:

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Here's an outfit that's been selling rf RC timers for 20 years...

http://www.amb-it.com/amb.asp

Imagecraft compiler user