Two Android phones at the same time running RaceChrono?

Hi, I´m going on a TrackDay event in a couple of days.
My question is if I can have two Android phones in the car, both running RC, recording data from my external GPS-receiver?
I want to have one phone on dash showing (and recording) lap times, and a second phone at the back video recording the runs, including GPS-data from the same external GPS-receiver (and OBD-II data)


  • Some external GPS can be connected from multiple phones, but I think that's rare. OBD-II can only be connected by one device.
  • Ok. Thanks. What is the preferred way to do accomplish my goals?
    - use internal GPS on laptime phone and external GPS for video-recording? (or vice-versa)
    - use external GPS on laptime phone and then import recorded video + OBD-II data to laptime phone lap session?

    To repeat my goal: See my laptimes during race, and video record the session, including HUD for GPS- and OBD-II data?
  • Recently, I'm doing this via screen mirroring, it has a delay about 0.1s though :

    - connected through samsung flow (for stable wifi direct screen mirroring, touch available)
    - samsung android tablet, mounted on dash (tab a 2019 for samsung flow support)
    - samsung s10, mounted on rear (s10 for wider camera angle like Gopro)
  • Can you just use an external camera for video recording? This way you should be able to use just one phone.

    Another option is to use Android Auto to project RaceChrono on the head unit in your car, see example here:

  • edited September 18
    Regarding Samsung flow, I guess my S6 is too old for that...?

    Regarding external camera: I have no external camera.

    IF I go for the option to have the S6 on dash with INTERNAL GPS, what accuracy will I get on laptimes? If internal GPS is 1Hz, will I get laptimes +/- 1 second?

    timurrr: nice setup with Android Auto! (But my car is a 1975)
  • Can you get a used GoPro? Sounds like the simplest solution here.

  • this is my RC setup for your reference :
    it will be quite same if you use AA, like @timurrrr says
    (only difference is wired or wireless)

  • ppanda, I´ve just read about Samsung Flow, sounds very nice!
    I guess you mean that you both control RC on the S10 in the back, from your dash phone, and also display RC output from the back phone, i.e you are NOT running RC at all on the dash phone? That´s cool.

    Nice video too! What track is that?
  • edited September 21


    Yes, my S10 does recording RC video in the back and streaming to the dash tablet at the same time. And touch is available on the dash tablet so you can control RC on it. No more copying video files from Gopro and sync tasks.

    And the track is INJE speedium in South Korea. Big up and downs. Isnt it? :D

  • Hmmm... I downloaded Samsung Flow on both phones. Install went good, but when I start the app on any of them it says "Start configuration of Samsung Flow on your computer or tablet".

    Maybe it won´t support to use 2 Samsung phones....? :(
  • samsung flow only support the connection between a phone and a tablet .

  • edited September 22


    If you are okay with non-touch on the dash phone, try this :

    * mobile hotspot connection.

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