GSP Laptimer Suggestion
08-28-2010, 06:07 AM
#16
Rennlist Member
I have used HLT and Traqmate at the same time, and the times are exactly the same. You can't do much data analysis, and the data rate is not even close, but even the graphs and diagrams are helpful. In mt experience, the Tom Tom Kit helps, but is not absolutely mandatory. And I have been able to do video overlays too. More tracks are constantly being added. Just send Harry an email requesting a track, and for the newer tracks that aren't visible on Google maps yet, send him your data and he'll make the track points available to all. He answers email questions quickly, and it's a great thing for the ~$30.
08-28-2010, 03:01 PM
#18
Race Director
Thread Starter
I just downloaded Harry's Lap Timer on my iPhone4. I will not be at the track (Sebring) until next month. I'm looking though all the things Harry's Lap Timer does and trying to figure out how to set it up for laps at Sebring....hummmm....
I need to figure out a safe and sturdy way to mount my iPhone4 in my car so I can use this app.
Does anyone know if I can use Harry's Lap Timer with my iTouch...does iTouch have GPS?
I need to figure out a safe and sturdy way to mount my iPhone4 in my car so I can use this app.
Does anyone know if I can use Harry's Lap Timer with my iTouch...does iTouch have GPS?
08-30-2010, 02:57 PM
#21
Burning Brakes
Yes (and I see he's gotten around to adding Heartland Park, but still no Hallett)
I think the only thing the provided track definitions have, is a set start/finish line, which still relies on the accuracy of your GPS signal. The problem with the iphone is that its intrinsic GPS antenna/processor isn't powerful enough to accurately or consistently record your times at racetrack speeds - at least in my experience. That's why both Harry's and Track Pro recommend the use of an external GPS receiver, like the Tom-Tom kit.
I think the only thing the provided track definitions have, is a set start/finish line, which still relies on the accuracy of your GPS signal. The problem with the iphone is that its intrinsic GPS antenna/processor isn't powerful enough to accurately or consistently record your times at racetrack speeds - at least in my experience. That's why both Harry's and Track Pro recommend the use of an external GPS receiver, like the Tom-Tom kit.
The second session, it seems to have recorded all the laps, but in one instance, it combined two laps into one. That is, it failed to record my crossing the start / finish line until the next lap. The third session, it recorded about half the laps, twice missing the finish line and combining laps. I am not sure of what made it quit, but the application consumes all the power available. Even plugged in, it drains the battery rapidly. It may have quit because the phone quit. I am not sure.
In each instance, the speeds seem off. For example, top speed seems 15 mph low. One presumes this is a GPS polling error. I don't think my speedo error is that bad.
For some reason, it just will not export data. It goes through a routine of composing the export files and then purports to be sending them to email, but the email function never opens, so it never goes anywhere.
Bottom line is that with the supplemental GPS, it is mildly interesting to get some lap times, but you will never get consistent information. Perhaps a newer iPhone would do better, but I suspect it would not be enough better to make this worthwhile.
08-30-2010, 05:36 PM
#22
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IMO, Harry's GPS Lap Timer is the best for displaying lap times in the car, and Log Box (from the makers of Dynolicious) is the easiest for simply logging data (which you can use for a video overlay and such). MaxQData also has a free iPhone app that may be worth looking at; I haven't had a chance to play with it yet.
Smartphone GPS reception is an issue inside cars... the iPhone's GPS works well enough for navigation, but to get any sort of precision for a datalogger / lap timer, you'll want to experiment with different mounting locations. A good start is under the front windshield, so that it has a clear view to the sky. However, even in optimal conditions, you only get 9m accuracy and a 1Hz sample rate, which is a big difference from a dedicated datalogger. My iPhone 4 does seem to have better GPS reception than my old iPhone 3G, but it appears that the same maximum accuracy and update speed limits still apply.
Smartphone GPS reception is an issue inside cars... the iPhone's GPS works well enough for navigation, but to get any sort of precision for a datalogger / lap timer, you'll want to experiment with different mounting locations. A good start is under the front windshield, so that it has a clear view to the sky. However, even in optimal conditions, you only get 9m accuracy and a 1Hz sample rate, which is a big difference from a dedicated datalogger. My iPhone 4 does seem to have better GPS reception than my old iPhone 3G, but it appears that the same maximum accuracy and update speed limits still apply.
08-30-2010, 08:17 PM
#23
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Smartphone GPS reception is an issue inside cars... the iPhone's GPS works well enough for navigation, but to get any sort of precision for a datalogger / lap timer, you'll want to experiment with different mounting locations. A good start is under the front windshield, so that it has a clear view to the sky. However, even in optimal conditions, you only get 9m accuracy and a 1Hz sample rate, which is a big difference from a dedicated datalogger. My iPhone 4 does seem to have better GPS reception than my old iPhone 3G, but it appears that the same maximum accuracy and update speed limits still apply.
Fortunately, the price of such GPS receivers has come down in price recently, and you can get an external bluetooth GPS receiver to work in place of the internal one built into your smartphone (e.g., the Qstarz BT-Q818X or BT-Q818XT models; I have the BT-Q818XT myself.) Works a treat for street navigation, too; gets a GPS fix in seconds rather than minutes.
I'm running this set-up with a Nokia 5800 running the Racechrono app (www.racechrono.com).
