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DIY GPS data format?

I'm starting a project to build in a GPS onto my bike so I don't have to mess with a GLO anyone. What GPS message format does RaceChrono expect? I saw there is a great thread with RC3 format information, but I haven't seen equivalent for GPS

Thanks

Comments

  • http://www.gpsinformation.org/dale/nmea.htm

    RaceChrono needs either combination of $GPGGA/$GPRMC or $GPRMC/$GPZDA/$GPVTG
  • Perfect, thank you!
  • Most of the GPS chips will output in NMEA format, so it might be that all you need to do is to re-route the data over Wi-Fi or Bluetooth.
  • That's the plan...

    I've managed to get some GPS data to pass through to serial. I'm debugging a bad string though. And I've managed to get a bluetooth connection... so debugging then put it all together! It sounds so easy
  • Just to verify, RaceChrono only logs RC3 acceleration data, correct? It isn't used for any GPS augmentation or correction?
  • @ManMan, that's correct
  • Well, this project got put on hold for awhile, but I'm back at it again.

    I've got NMEA sentences passing through Bluetooth to my phone and RC will connect and show a data rate, but says "No Satellite fix - Waiting for data...". I'm able to read the following via a terminal app

    RMC+GGA only
    $GPRMC,161302.000,A,3xxx.2537,N,0xxxx.0049,W,0.02,348.22,060518,,,D*7A
    $GPGGA,161303.000,3xxx.2537,N,0xxxx.0049,W,2,08,0.98,172.0,M,‑24.3,M,0000,0000*5D

    Also tried a full dataset. But still "No Satellite fix - Waiting for data..."
    $GPRMC,161302.000,A,3xxx.2537,N,0xxxx.0049,W,0.02,348.22,060518,,,D*7A
    $GPGGA,161303.000,3xxx.2537,N,0xxxx.0049,W,2,08,0.98,172.0,M,‑24.3,M,0000,0000*5D
    $GPVTG,348.22,T,,M,0.02,N,0.05,K,D*30
    $GPGLL,3xxx.2537,N,0xxxx.0049,W,161303.000,A,D*4B
    $GPGSA,A,3,08,09,27,26,16,03,07,23,,,,,1.57,0.98,1.23*02
    $GPGSV,3,1,12,23,68,169,36,09,65,301,17,27,48,087,28,08,45,149,28*71
    $GPGSV,3,2,12,44,45,214,32,07,34,304,16,16,32,041,24,30,11,289,15*7D
    $GPGSV,3,3,12,03,09,195,19,26,06,050,29,28,04,232,18,11,03,170,15*7C

    Connecting via USB to my computer I see the same messages and am able to get a positional lock and info (although no magnetic info from RMC)

    What am I missing to get my setup working with RaceChrono? I've tried pairing/unpairing; "Bluetooth fix" on and off.

    Thanks
  • Can you send me uncensored NMEA feed (like 5 minutes worth) to tracks(at)racechrono.com ? I will take a look why it's not working. Please compress it to .zip so linefeeds etc will remain intact when I download it.
  • email sent! Thank you for the help
  • Just checking to see if you had been able to look at the files I sent
  • Hi, you have broken line feeds \r\r\n. RaceChrono does not recognise this as it needs \n or \r\n. I've fixed it to allow \r\r\n in future, but won't release in a while, and I guess it's worth fixing anyways.
  • That fixed it, thank you!!!

    I changed readStringUntil('\r') to readStringUntil('\n')
    and serial.println to serial.print

    The extra \r is gone and app is connecting/receiving perfectly!
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