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FIXED -Laptimer2000 one lane has gone dead after 7yrs

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  • FIXED -Laptimer2000 one lane has gone dead after 7yrs

    I have 1 out of 2 lanes that just went dead. Before it died it was recording the Lap 1sec late! The car would go under and then 10ft later you would hear the F1 was intermittent too.
    Now it won't register at all.
    Are the emitter lights on?
    -yes, I can see the purple color on both emitters with a digital camera

    Did you move the emitter around to improve alignment?
    -yes no motion of the emitter will register a lap

    The good lane fires at will, every time you wave a finger.

    Did you vacuum the hole where the receiver is?

    What does the I/O Port testing show?
    -good lane is CLOSED at rest, then when car goes under triggers open for a split sec. then back to CLOSED
    -deal lane is OPEN all the time

    My next step I think is a tear down of the nice permanently mounted gantry...and look for a loose photocell or dirty cell.
    New 2 lane parallel port cable is $120us...
    Thoughts? Thanks in advance.
    Last edited by Ross Turek; 03-01-2016, 09:52 AM. Reason: found the solution

  • #2
    For completeness: I checked my settings
    TrackMate Compatibility setting WAS NOT checked, so I checked it, no fix.
    Again one lane is working perfectly and one is dead.


    • #3

      I use 940nm IR detectors and emitters for my lap timing. I measured my detectors with a volt-ohm meter and measure > 1 meg ohm dark and about 700 ohms hot. You can use an incandescent lamp to light the detector to rule out your emitter as a cause. Go to your good circuit and measure the resistance and voltages when the detector is dark and hot to help evaluate the defective circuit. One issue I had with my original setup was finding the " sweet spot" where my parallel port would trigger. I originally used resistors in series and parallel with the detector to get the detector to trigger accurately and not be influenced by ambient light. The resistor values I used were also different between lanes 1 and lane 2. If your components are 7 years old, they may have changed value and now not triggering the parallel port. Myself , I ended up replacing the resistors with a differential IC amplifer circuit that gives 0v and 5v for dark and hot.

      Good Luck,



      • #4
        It sounds to me like the sensor for the bad lane needs to be replaced, either that or the connections to that sensor are not good. If you know which pins at the computer end of the cable go to the sensor you can unplug the cable and check the continuity to the sensor.


        • #5
          Rich & Mike tks. Will compare resistance of good and bad lane. Also will tear apart timing gantry and look for loose sensor or dirt.

          Mike is this what you use?

          Sent from my SM-T800 using Tapatalk
          Last edited by Ross Turek; 02-08-2016, 08:49 PM.


          • #6
            These are the NPN's I use to build Laptimer 2000 cables. Don't forget the collector is the short lead / emitter long lead when you replace the possible faulty IR Phototransistor.


            Last edited by cgyracer; 02-08-2016, 09:05 PM.


            • #7

              The Radio Shack 276-0145 are phototransisitors.
              These are called out in the laptimer2000 hardware.

              The 276-0142 uses Photodiodes and will not work as a direct substitute.



              • #8
                FIXED -sensor skewed

                Complaint: Late (1-4sec) laps being recorded on Laptimer2000 after 7 yrs of success and then eventually no laps at all.
                Cause: Bad lane had sensor glued at an 15 deg angle and not centered in track hole
                Correction: Increase track hole diameter, center the sensor in the hole and glue with hot melt adhesive
                Photos later today. It is amazing it worked at all for the 7 yrs.
                Last edited by Ross Turek; 03-01-2016, 10:15 AM. Reason: update complaint


                • #9
                  Great news, Ross!...

                  Really glad you found the problem...



                  • #10
                    Photos of defect Red Lane

                    Red lane sensor barely visible, first clue why no work

                    Red lane sensor glued at a 15deg angle, amazingly it worked at all for 7 yrs. Blue lane nice and flat.

                    So much glue on the sensor it could barely see up to the gantry lights
                    Last edited by Ross Turek; 03-11-2016, 05:24 PM.


                    • #11
                      Still working 100% December 2016


                      • #12
                        Glad to to hear it is fixed and working!

                        Yes indeed!

                        Merry Christmas and Happy New Racing Year!