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  • Power for dead strip...

    I've got a 2-land Scalextric track, with a homemade dead strip, and connected to a PC, running WinXP, via LPT1.

    I'm a little confused about where the power is supposed to come from, to complete the circuit, when a car crossed the dead strip: does the power come from pin 25, or is the power supposed to come directly from the track power source?

    Thanks.


  • #2
    The dead strip itself is not powered. If you stop your car on one it will not run. If the dead strips are on a spot where the cars go full speed they will cross the dead strips without slowing. There is a voltage across the dead strips that comes from the computer port, when a car crosses the dead strip that causes a drop in the voltage and triggers a count. You never want to apply a dead short across a computer port, that can cause it to burn out, so there should be a resistor in series for each lane. You also need to make sure that track voltage can't get to the port.
    There is a lot of info on dead strips here: https://docs.google.com/file/d/0BzLR...?usp=drive_web

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    • #3
      I understand how the dead strip is supposed to work, except for one fact: if, as you say, "there is a voltage across the dead strips, that comes from the computer port...", does this mean that the "input pins" actually are sending out a constant voltage, and register a signal, when the voltage drops?

      I guess I was expecting it to work more like an analog switch...

      Sent from my SGH-M919 using Tapatalk

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      • #4
        Yes! That is the case with regular dead strips because the car's motor will be in the circuit. With inline and split rail dead strips only one braid is needed to trigger a count and the car's motor is not is not in the circuit. Dead strips actually work the opposite way from what you would expect.

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        • #5
          Thank you. So, to clarify, I should have one side of the dead strip (per lane) connected to an input pin, and the other side connected to a ground pin, such as pin 25. Do I have that correct?

          One final question : is it exactly the same, regardless of whether it's a standard dead strip, or an inline strip (mine is inline...)?

          Sent from my SGH-M919 using Tapatalk

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          • #6
            Yes, that is correct, but don't forget to include a resistor for each lane. If it is a car that closes the circuit and you don't have a resistor it is unlikely that the port would be damaged, but if something shorted the rails it would probably get cooked. The other issue with regular dead strips is polarity, they only work properly in one direction.
            Last edited by RichD; 04-25-2014, 06:59 AM.

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            • #7
              OK... what tests can you do?

              Honestly I have everything set up exactly as discussed, and I still can't understand why it's not working...

              Sent from my SGH-M919 using Tapatalk

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              • #8
                You may have to tell the software which port to look at. I am not familiar with the way Ultimate Racer works with respect to that, Trackmate will tell you if it does not see a port and and has an autodetect feature that is usually able to find the correct port. Possibly your serial port is burned out. Possibly your computer does not work with the software that you are using. Do your dead strips have guard strips?
                Last edited by RichD; 04-25-2014, 07:11 AM.

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                • #9
                  I don't mean to sound snarky, but since I posted this in the Ultimate Racer technical forum, I simply assumed that a reader would realize that I am running Ultimate Racer. Also, as I mentioned, in my first post, I am using a parallel port. It doesn't seem to be a problem with the port, itself, nor with the software (unless I have it configured improperly)...

                  Sent from my SGH-M919 using Tapatalk

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