iPhone as laptimer--good enough?

[ChrisZang]

detailed writeup can be found here:
Porsche Club of America Golden Gate Region • View topic - experience with GPS based lap timer system

a few errata to my writeup (please read the writeup first)
The 10 Hz GPS I intially used died and I replaced it with a - cheaper - 5 Hz unit which does the job just as well
The company (MaxQData) which made the PocketPC version then also created an iPhone version but then went out of business
I have their iPhone product and Harry's lap timer both installed on my iPhone and very much prefer their product, reasons being:
* faster, more accurate sampling points
* supports landscape mode
* predictive lap timing
Apparently CMS has taken over the product but in all fairness I never tried their version
Any GPS lap timing on the iPhone is limited by the fact that the sampling rate of the "location service" is limited to 1 Hz no matter how fast the GPS is that you have connected

I have added two pics which show my setup
The mount is a GoPro mount which I had laying around and you can see the GPS module sitting on top facing towards the sky

[MikenOH]

Thanks again Chris--more questions:

-Dell Axim(?) PDA? I take it it's purpose is to display the lap time and save the info?

-Unless I missed it, how are you overlaying your video from the GoPro with the data from the Axim?

thanks, Mike

[ChrisZang]

Yep it does both records the laps and displays the laps live
The overlay is described at the end of the link I posted above