Harry’s lap timer pro versus a Transponder

captahole · Post by **captahole** » Mon Jul 09, 2012 5:08 am

http://outrageousracing.squarespace.com ... onder.html

just a little info for you guys.

Erik
Owner/Driver Outrageous Racing
#14 NSX

Post by **Harry** » Mon Jul 09, 2012 8:41 am

Hi Erik,

Thanks for posting. That's the approximate accuracy one can expect with the internal GPS for iPhone 4 and 4S. Two comments however, the third digit it not a hundreds but a thousand of a second. Second is, how much is the deviation from "reality" delivered by the transponder system

People tend to take this as the truth. However, I doubt they deliver the accuracy the suggest by showing thousands.

Harry

Dubbedown · Post by **Dubbedown** » Tue Sep 04, 2012 3:11 pm

Wow makes me wonder if the Emprum is even worth it seeing how accurate ip4 is!

csmarx · Post by **csmarx** » Wed Sep 05, 2012 3:54 am

Dubbedown wrote:Wow makes me wonder if the Emprum is even worth it seeing how accurate ip4 is!

On that note, I'd love to see a comparison of LapTimer Pro with a 5 Hz external GPS chip, such as Emprum or Dual vs. a transponder. Anyone have such data?

-Christian

Post by **Harry** » Wed Sep 05, 2012 7:26 am

Accuracy data is documented here: viewtopic.php?f=6&t=459&p=2091

It is derived from numerous reports and some calculations.

But maybe some can post real life data.

Harry

MStephens · Post by **MStephens** » Sun Sep 23, 2012 4:46 pm

Interesting. My car has a Blind Apex timer installed, which uses the car & track transponder circuit to report lap times, and I find differences that are less accurate than those reported with Harry's GPS here. I often wonder if my car's report is more or less accurate than the track's timing (I'm sure it is not, but when my car reports quicker times by a few tenths I want to believe it.)

Post by **Harry** » Sun Sep 23, 2012 4:59 pm

Do you have a concrete report from the timing system? Maybe you pick a lap with a too big discrepancy, export it to .hlptrl, send it to me, and add the time the timing system believes in

I will check and tell you which one is wrong

- Harry

MStephens · Post by **MStephens** » Sun Sep 23, 2012 5:08 pm

Harry wrote:Do you have a concrete report from the timing system? Maybe you pick a lap with a too big discrepancy, export it to .hlptrl, send it to me, and add the time the timing system believes in I will check and tell you which one is wrong

- Harry

I'm racing in a couple of weeks and will send you some full reports. It will be my first time using HLT, and while I can't export data from the Apex system in the car, I'll write those down and get individual lap times from the official track report.

Post by **Harry** » Sun Sep 23, 2012 5:15 pm

Oh, I understood you got differences between the timing system and LT... So please forget my last post. Which accuracy is stated for your Blind Apex timer? My guess is they should not be too different - although the factors that influence accuracy for transponder systems are different ones compared to GPS based systems.

- Harry

MStephens · Post by **MStephens** » Sun Sep 23, 2012 5:23 pm

Harry wrote:Oh, I understood you got differences between the timing system and LT... So please forget my last post. Which accuracy is stated for your Blind Apex timer? My guess is they should not be too different - although the factors that influence accuracy for transponder systems are different ones compared to GPS based systems.

- Harry

They don't state accuracy, as the claim is that it is the actual data from the AMB transponder system.