Anyone iPhone Apps for Track Driving?

[Noel]

Got my iPhone a couple months ago and saw a few apps that promise real time and recorded LapTimes via GPS, track mapping with measurement of braking/accelerating and g-forces. I only do DE, but I was considering a Traqmate this year to help me keep up with my slow car in the Black group. However, with all of the cool stuff coming out for iPhones, I thought I would wait to see if a similar program is developed that logs data and allows for offline analysis. Anyone know if any yet?

I just found G-Tac Pro, which looks good for $20.

[barney911rs]

Someone, Grassroots Motorsports maybe, did a review not that long ago about data acquisition devices, and they did an Iphone. It was the lowest rated, but they were impressed by what it did.

[WestonP22]

G-Tac Pro seems pretty interesting... I had been tempted to write an app like that myself for some time now, because nobody seemed to care enough to log GPS + accelerometer data. Their website really doesn't tell me much though: http://www.libertyforone.com/g-tac/g-tac-pro

I would be most interested in what format it exports the GPS and accelerometer data in, because I don't think you're really going to do much useful analysis on the iPhone itself. But if you could easily dump the data to a computer and analyze it there, then you might have a decent learning tool, rather than just a neat gadget for show. Obviously, it doesn't have the precision, accuracy, or array of features that something like a Traqmate does, but for $20 that could be a really sweet deal (the cheapest Traqmate is $699 MSRP, or $600 if you get a good deal new), and you could potentially do neat things with the data like video overlays.

I'm somewhat tempted to just buy it and mess around with it, but would really prefer more information first. If it does what I'm thinking it does, I could do a side-by-side comparison with Traqmate in my car (I just finally ordered one for myself), except that I still have 4 weeks until my first race this season...

[DByers]

I have a program called Track Day on my iphone. Good app for the money but not able to download info to my computer. I also have the G-Tac Pro but have yet to get it to the track. I will be doing a side by side comparison of the 2 on April 30th. The Track Day program was with in 2/10th of a second compared to my transponder my last outing at streets.

[WestonP22]

I couldn't resist my curiosity and downloaded G-Tac Pro last night... I've only played with the lap timing on the street in my truck so far, but from what I've seen it's a really simple and easy to use app. The only problem I ran into was getting the iPhone to get a strong GPS signal inside my truck, but it does compensate for that somewhat... the output data indicates the precision level of each GPS sample, and it only writes GPS info when it is able to, so sometimes you see GPS samples that are a few seconds apart, and other times you see 1 or 2 per second. The really good news is that the accelerometer data appears to be sampling at 30Hz, which fairly high.

The app records the data, shows you your Max G's and speed, and plots it all along with the map of where you were. It does not give you much for doing analysis, but I wouldn't expect that from an iPhone app either. The big deal here is that it can export it's raw data. The output data is a raw CSV dump that you e-mail to yourself from the iPhone, and it consists of two separate sections... GPS data and accelerometer data. I am now tempted to put together a simple program that combines the two sections, uses the accelerometer data to interpolate the GPS data (this is what most big name dataloggers do), maybe does some simple analysis, and exports a nice CSV file that can be overlaid onto video using RaceRender, TrackVision, or Dashware. That would make this a much more feasible datalogging solution.

Here is a quick sample of what the data export looks like...

Description:
Date: Mar 22, 2009 12:41 AM
Elapsed Time: N/A
Top Speed (GPS): 26mph
Max Accel. G: 0.33
Max Brake G: -0.34
Max Left G: 0.52
Max Right G: 0.27
Notes:
Enter Notes

========= GPS Data =========
time (sec),Latitude,Longitude,Accuracy (m),Speed (m/s),Course (deg from N)
0.00,39.996253,-105.086782,17,0.000000,90.000000
2.19,39.996243,-105.086696,17,0.000000,90.000000
3.38,39.996232,-105.086610,17,8.025333,94.000000
4.28,39.996221,-105.086524,17,7.510889,94.000000
4.87,39.996221,-105.086460,9,8.951333,92.000000
5.78,39.996221,-105.086331,9,10.906222,90.000000
6.26,39.996221,-105.086288,9,10.288889,90.000000
6.87,39.996221,-105.086160,9,10.649000,90.000000
7.56,39.996221,-105.086074,9,10.186000,90.000000
8.38,39.996210,-105.085967,9,10.803333,90.000000
...

======= End GPS Data =======

==== Accelerometer Data ====
time (sec),RPM,Longitudinal Gs,Lateral Gs
0.00,0,0.000,0.000
0.01,0,0.102,0.000
0.06,0,0.128,-0.002
0.10,0,0.155,-0.001
0.13,0,0.179,-0.001
0.17,0,0.202,-0.001
0.20,0,0.225,0.003
0.23,0,0.246,0.003
0.27,0,0.263,0.005
0.30,0,0.278,0.003
0.33,0,0.292,0.001
0.37,0,0.301,0.008
0.40,0,0.312,0.011
0.44,0,0.318,0.016
0.48,0,0.323,0.017
0.51,0,0.322,0.017
0.55,0,0.326,0.017
0.58,0,0.325,0.016
0.62,0,0.325,0.012
0.65,0,0.324,0.009
0.68,0,0.324,0.008
0.72,0,0.323,0.005
0.76,0,0.325,0.003
0.80,0,0.323,0.002
0.83,0,0.321,-0.000
0.87,0,0.324,-0.002
0.91,0,0.321,0.001
0.94,0,0.315,0.005
0.98,0,0.316,0.010
1.02,0,0.318,0.015
...

== End Accelerometer Data ==

[Noel]

That is very interesting. I'm sure it won't be long before we have a program that can analyze this. In fact, if I was Traqmate, I would write a program for use on the iPhone as sort of a Light version of Traqmate. It will never do everything that the Traqmate complete will do, but right now the price differencial between $1,000 for a Traqmate Complete and an iPhone app is too big and only serves a motivation for potential competitors.

[WestonP22]

I tried both G-Tac Pro and LogBox last weekend, along side my Traqmate. G-Tac is my clear preference of the two iPhone apps... it's simple to use, can replay the session on the phone, the data export is two simple CSV sections, and it doesn't let the phone lock when you have an unexpected 20 minute delay in grid. Unfortunately, both suffer from the iPhone's GPS reception issues. It seems that the center tunnel is a great place to mount an accelerometer, but not so great for a GPS antenna. Because of that, I was only able to compare accelerometer data this time. I hope to try this on the track again next month and will hopefully be able to collect GPS data then...

I've had people on multiple forums asking about this, so I put my G-Tac vs Traqmate comparison and video out there as HTML that I can link everyone to... http://www.rm944.com/weston/iPhone/G-Tac%20Pro%20vs%20Traqmate%20-%20090419.html


As for LogBox, it lacked sufficient GPS data as well (I mounted the iPhone in the same place for both apps), and it doesn't give me a clear time-stamp on the accelerometer samples, so I don't have anything put together for it right now. Basically, it was writing multiple samples with the exact same time values, and it didn't log at a steady 20Hz like I set it to, so that really leaves something to be desired. I would hope that future updates correct that...

[rlh930]

I got G-Tac Pro and tried using it at an autocross. Overall I'm pretty impressed, and it's certainly worth the $20, but there are a few things to mention:

1. Remember to set the iPhone not to power down (Settings/Auto-Lock/Never.

2. The GPS is slow to acquire unless it can see the sky. I bought a mount that places it in front of the ventilation ducts in the center of the dash (and has a power cable to keep the iPhone charged :-). This seems to keep the GPS happy.

3. You can't work the iPhone touch screen when you have gloves on, so it's hard to start/stop a run. You could of course cut a hole in the fingertip if you're not worried about fire protection. Otherwise you're stuck with a lot of dead time before and after the data you're really interested in.

4. The GPS position data doesn't look particularly accurate. The GPS track roughly corresponded to the AX course layout but by no means exactly. On the other hand the speed data looked reasonably accurate.

5. The accelerometer data was somewhat skewed. When I was stopped, the accelerometers showed me with around .1G of longitudinal and .01G lateral acceleration. This was consistent and if you export to a PC, you can easily remove it with Excel, but there doesn't appear to be a way to calibrate the unit except to fiddle with the iPhone's orientation in the car.

6. The time values for the GPS and accelerometer data were significantly out of sync (at least a second or more). The GPS speed and direction showed me at the end of a straight long after the accelerometer showed I had entered the turn at the end. Again, with a little experiment you could probably post-process this out with Excel.

Nevertheless, it's pretty incredible to get a completely self-contained data logger for $20.

[Noel]

Great posts guys. You've convinced me to download G-Tac prior to my Mid-Ohio DE. I was also considering buying a Traqmate this year too, but am now waiting.

[nvrupnvrin]

Does this only work with the new iPhone, the 3G, or will it work with the earlier version?

[Driver8]

You will need the new 3G iPhone, because it has GPS.

[nvrupnvrin]

Thank you

[WestonP22]

Based on the reviews for the app, it looks like the original iPhone will work... it just provides accelerometer data only since it doesn't have GPS built in. Same goes for the iPod Touch.

[fredmeister]

Dynolicious is a good one for the I-touch since it does not have GPS ability. $12.99 and it is pretty good. Cannot track map or eport data, but will plot skidpad and graph values so you can pick out max and min values for a run. It does 0-60, and hp too. Seems reasonably accurate as long as you get the weights of the car correct.

[Grantsfo]

Harry's GPS Lap Timer

http://www.gps-laptimer.de/

Biggest issue with all iPhone GPS based lap timers will be the poor cycle time of the GPS unit. Wish somone would do something to allow a blue tooth connection to an external GPS reciever that has better cycles. I have seen smart phone apps that work well data logging software and an external bluetooth GPS reciver as well.

[WestonP22]

Originally Posted by Grantsfo

Harry's GPS Lap Timer

http://www.gps-laptimer.de/

Biggest issue with all iPhone GPS based lap timers will be the poor cycle time of the GPS unit. Wish somone would do something to allow a blue tooth connection to an external GPS reciever that has better cycles. I have seen smart phone apps that work well data logging software and an external bluetooth GPS reciver as well.

That's an interesting app. Anyone have a sample of the CSV data it exports?

With iPhone OS 3.0, we are supposed to be able to connect external 3rd party devices to the docking connector, so a more accurate and external GPS receiver could be pretty useful for this purpose...

[nvrupnvrin]

Could anyone tell me the best way to mount the iphone? I would like to try it for a DE, but the club says all mounts have to be metal to metal.

Thanks

[petrolhead611]

Does anyone know if G-Trac Pro works on Blackberry Storm?
I mount the phone on its standard suction flex arm onto the windshield and get almost rock steady video of AutoX runs.

[WestonP22]

Originally Posted by nvrupnvrin

Could anyone tell me the best way to mount the iphone? I would like to try it for a DE, but the club says all mounts have to be metal to metal.

Thanks

Metal to metal is going to be hard. I just put Velcro on the back of a hard plastic iPhone case. My Traqmate is also mounted using Velcro. Just don't put it somewhere that gets hot and you should be ok.

[petrolhead611]

Now loaded Dynolicious onto my Blackberry Storm. Am going to compare its capabilities with my old Racelogic box that I velcro mount to the dash of my Vindicator( don't want to put Velcro onto the uncracked dash of my Porsche.