External sensor for using magnetic strip in track for lap timer

Hi There, I am looking at buying this program for use on my Sons kart. I am wanting to trigger the lap timer with a hall sensor that will pick up the magnetic strip on the start/finish line. Is this possible? I was thinking I could possibly use a keyboard controller and make a circuit to effectively press a button. The electronic side of things is not a problem, but the coding side is for me. Any information would be great. Thanks


  • Currently there's no such feature in RaceChrono, as it uses GPS data to calculate the lap times. I have thought about this feature, but I'm unsure how I should combine the magnetic strip triggers with the GPS data... Any ideas?
  • I am also interested in the hall sensor that would pickup the magnetic lead. Do you have a particular sensor in mind? One that would be sensitive enough that would to pickup the magnetic strip.
  • That is a shame. My thought would be to use " android switch access" or the switch that is connected via the 3.5mm headphone jack. Have an option in your menu to choose an external trigger or GPS for lap timer. If you go the external keyboard way, you could scroll through options via mapped buttons. I was thinking about making a case to house a LED rpm gauge and a cheap phone with 4 or so buttons for navigation. Touchscreens are no good with gloves so buttons are better.

  • edited November 2019
    I have no problem providing an API for this, more specifically adding a simple ON/OFF characteristic to my DIY project, if you think it would be useful? You would not need to implement the other functionality on the device, just the magnetic strip trigger would be enough. Project link: https://github.com/aollin/racechrono-ble-diy-device

    Other option (that you could already use) is to implement RC3 output on a Bluetooth RFCOMM device, but it works only on Android phones: https://racechrono.com/article/2572

    But more important question is how would you use this magnetic strip data? Would it be useful to have it appear in the graphs only? As RaceChrono is GPS based lap timing, and everything is build around it, I don't think lap timing based on the magnetic strip would be wise use of my limited R&D time... ?

  • Thanks for the links. I will have to look into it when I fly back home. I think it may be a bit of messing around, and when you already have a great working product, it is understandable that you can't spend time on catering for everyones needs. I originally thought I would ask the question to see if anyone had done something already and didn't expect you to invest any time in it. I really appreciate your willingness to offer help/suggestions. It's great to see a developer willing to listen. Cheers

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