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A project called RaceChrono – GPS lap timer

July 22nd, 2007 - Track

It all began as my idea of a mobile phone based lap timing software. Using GPS is nothing new in the lap timing business, but what made the idea exciting to many, was the possibility to use a commonly available smart phone together with a cheap Bluetooth GPS instead of expensive purpose made hardware. I made a proof-of-concept in a few weeks, which inspired a few other Carfreaks and quite soon RaceChrono was born.

About a month ago, after several hundreds of hours of work, extensive testing and many laps driven, we finally felt that our project was ready enough to go public.

First live timer screenshot

The main feature is of course the Live Timer, which shows your lap- and sector-times in real-time. Also included are a scalable graphical display of traveled path, satellite reception display, speedometer and a compass:

Second live timer screenshot

When you’re back at the pits, you can also browse through your lap and sector times, or view your trap speeds:

Sectors screenshot

Or maybe analyze your laps by graphs of time, speed and altitude compared to any another lap:

Analyze screenshot

All lap timing sessions are logged, and the results can be viewed afterwards. The raw NMEA-output from the GPS is also saved, so you can use that in other compatible software if you wish.

And yes, there’s always the question of accuracy when it comes to timing anything. After extensive testing, we feel really confident on RaceChrono’s accuracy. Our tests together with commercial lap timers have showed an accuracy of between +- 0.03-0.10 seconds with a cheap 5 Hz receiver. Switching to an ordinary 1 Hz SirfStar3 receiver RaceChrono was still very accurate – on the level of +- 0.10-0.15 seconds. Keep in mind however that accuracy is fully dependent on the quality of your GPS receiver and signal reception. There is also an experimental performance testing feature in RaceChrono, but at the moment we would not rely too much on the individual results it gives.

Note that if the signal from the satellites is too weak, your lap times can be inaccurate and in worst case you can even miss some laps. So take care to position your receiver properly on your dash close to the windshield, or maybe even outside the car! Use the satellite reception display to help you find the best location in your car.

Currently supported phones are almost all Series 60 smart phones (specifically Series 60 2nd edition and 3rd edition). This means that tens of Nokia smart phone models are supported, and some LG and Samsung models as well. Nearly all Bluetooth GPS models are supported, but we recommend either a 5 Hz MTK chipset based or a common 1 Hz SirfStar3 based receiver.

I guess that’s all for now. Please visit the project web site at www.racechrono.com!

17 Responses to “A project called RaceChrono – GPS lap timer”

  1. Chakibrull Says:

    I Knew I had to buy a Nokia instead of an Ericsson…

    Nice job, ‘as usual’ ! ;)

  2. Moogie Says:

    It’s quite amazing what you’ve been able to put together in a very short time. RaceChrono is already in many ways equal to commercial alternatives, and when 10Hz bluetooth GPS modules become available someday, there’s no reason to use anything else. Oh – and did we remember to mention that RaceChrono is free for the time being!

    Want to let your friends know of RaceChrono, or just to help to spread the news? Just digg the story!

  3. PhoneFreak Says:

    Is there support for internal GPS, like N95/E90?

  4. Hunter Says:

    Is the support for Windows Mobile 5 device like Mio Digiwalker A701 with internal GPS

  5. aol Says:

    PhoneFreak: no internal GPS is not supported before we get our application certified in through “Symbian Signed” program.

    Hunter: Other platforms than Series 60 is not yet supported.

  6. Taka Says:

    I brought the i Blue 737 but I brought the 1Hz version. I think. Damn. I will test it against my AIMS.

    If it is consistantly 0.15 sec difference it is very acceptable.

    Do your screen goes to sleep mode while running? How can I solve that?

  7. aol Says:

    It should wake up when first lap starts. Probably need to create extra setting to enable the back light always.

  8. zanta Says:

    This is what I’ve wanted for long time.
    And it’s almost perfect :)
    10+ points for the developers!

  9. Andy Says:

    This is just brilliant. I was thinking of building something on a solid state device like the eePC. But your onto a much better idea with the Symbian platform. I look forward to trying it out and giving you some feedback.
    Well Done!

  10. Steptoe Says:

    Thanks. You made something I didn’t know I wanted until I found it. Even got all the tracks I use available.

  11. Mikethebike Says:

    For Windows Mobile Phones or WM PDA’s you can use iLap from ilaptiming.
    It works great… little less features, but doing a great job to replace a standard laptimer.


  12. aol Says:

    We are working on Windows Mobile version as well, so stay tuned!

  13. Isaac Says:

    Would be great if you could get a PC version of this! Have eeePC and usb gps mouse.

  14. Malkom Says:

    see this … http://www.sch-racing.com/en/index-1.html

  15. craig fisher Says:

    who makes a cigar socket powered / SD card enabled / WScreen suction mount / GPS laptime ETC downloader in UK ?

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