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lap timing circuit

Discussion in 'General Electronics Discussion' started by yamik, Aug 27, 2012.

  1. yamik

    yamik

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    Aug 27, 2012
    How can i make "lap timing circuit" used in car racing??
     
    Last edited by a moderator: Aug 28, 2012
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    What are you timing?

    How do you want to start and end a timing period?

    Is it for inside the vehicle, or outside?

    What about commercial options? Is there anything to learn from them? Why have you discarded them as an option?

    What is your budget?

    Is this to be fixed (at a particular circuit) or transportable?
     
  3. yamik

    yamik

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    Aug 27, 2012
    I have to make timming circiut for testing f1 racing cars.....
    And counting should start automatically when car speeds ups n stop immediatly wen lap is over....
    The circuit should work both on circular and straight tracks....
    N there's no issue's regards budgets.....thnx 4r d hlp....
     
  4. yamik

    yamik

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    Aug 27, 2012
    It is not to be fixed....and it has to be outside the car....
     
  5. rodrilyx

    rodrilyx

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    Aug 29, 2012
    You can use a timer 555!
     
  6. BobK

    BobK

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    Jan 5, 2010
    Yes, and you could also use a person with a stopwatch.

    Bob
     
  7. rodrilyx

    rodrilyx

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    Aug 29, 2012
    Too! :D
     
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Presumably there will be other vehicles on the track, so the means must involve something that either won't detect other vehicles, or will discriminate between them.

    I guess there are plenty of safety standards that limit what you can place around the track near where the vehicles might be, so preferably it needs to be able to detect the vehicle at a distance.

    One option might be to attach a small transmitter to the vehicle and then determine using the Doppler effect, whether the vehicle is approaching or receding from the receiver.

    If you can detect the rate of change of frequency, the time when the vehicle is closest to the sensor is the time when that rate of change passes through zero (and changes sign).

    This would need to be tested to ensure that it detected the vehicle at the same point whilst it was travelling at different velocities, was under acceleration, or took a different line, or if it was in traffic.

    Another option might involve cameras and detecting the vehicle, however this might fail if you have more than one car that looks similar (as I guess team cars tend to do). The other issue with cameras is that you need to find somewhere to place them.

    Have you tried GPS receivers? Even if you can get a position only every second, you should be able to interpolate. Of course this would be very sensitive to acceleration. Perhaps it could be augmented by a pair of sensors that track acceleration in 2 axies. This should allow a better "dead reckoning" between GPS updates. This could be the core of an inertial position sensing unit which could be placed on the car allowing it's position to be accurately reported with the other telemetry that you doubtlessly stream from the car (in fact you may already track acceleration). It would be a lot neater if the car could generate its own splits -- makes it easier to set up a new track too, just drive around it (in another vehicle if you need to) and press a button to tell the device where you want splits.
     
  9. yamik

    yamik

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    Aug 27, 2012
    i want to make the circuit just to test the timming of car......In how much time it can cover the lap..........
     
  10. yamik

    yamik

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    Aug 27, 2012
    i m trying to use the software "x note" as the timer....but what i really need is "how to implement a circuit/sensor system"

    so basically i want to develop a system which starts the timer when car starts from the starting point and stops the timer when it passes through the ending point and its accuracy should be very high.......

    one more thing....there will be no other vehicles around the track...
     
  11. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    If there are no other vehicles around the track then you could probably just fire a laser across the track aimed at a corner reflector, and detect the beam being broken.

    Reflective tape is essentially all you may need, and if there are restrictions of what you can place inside the perimeter of the track you could tape it to a paper tube, or some other flimsy structure, or onto a tyre wall.

    The main issue is the range you'll get out of this.
     
  12. yamik

    yamik

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    Aug 27, 2012
    Ya i'll try using laser beam n a reflector.....if i get any error or sumthng ll get back 2 u...thnx 4r the help...
     
  13. yamik

    yamik

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    Aug 27, 2012
    hey can you help me out with the circuit diagram..........
    or a bit idea about it......
     
  14. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    What you want to do is set up an oscillator driving the laser at a moderately high frequency (say a couple of hundred to a couple of thousand Hz.

    The detector should be AC coupled to an amplifier and you should then XOR the output with the clock signal.

    As soon as the beam is broken, the output will change from mostly one state to mostly the other state. Passing this through a low pass filter to a schmitt trigger will yield a pulse whenever the beam is broken.
     
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