Yup! Thanks for sharing the app and your findings with us. I'm not gonna get to try out the new gps until the Blytheville race in three weeks. I'm signed up for the Evo advantage so that will give me plently of time to play with it.

 

Used Harry's LapTimer to record my runs at a local autox. The 1 hz update rate from the TomTom mount wasn't quite up to the tight turns and quick transitions, but the video start/stop was useful. Can't wait for the Standing Start support, though..

http://vimeo.com/24195670

This was my third time at autox.. lots of fun!

 

Nice progress through all those runs!

 

Here's my Sunday fun and some data from the fastest run...

I collected a bunch of data via iPhone running Harry's Lap Timer App from the May 22 event at the Marana Airport including two different videos for each run... everything below is from my fastest fun run with a time of 71.757 sec. In the plots below, the reference lap in red was 71.955 sec.

Comment on the app - the start GPS point was not working for some reason, so the system was manually started each run. The other intermediate GPS points and finish all worked to produce intermediate data (times, etc), but they did not show up on the resulting map or come out in the exported data (i.e. KML file)?

Videos
- Regular Video Camera
- iPhone with Overlay (Harry's Lap Timer)

Data

Speed (Top Speed 74 MPH)



Lateral Gs (Max 1.06 per iPhone accelerometer)



Peak as indicated by highlight on course map


Peak as indicated by highlight on course map


Peak as indicated by highlight on course map


Yellow = > 0.8 G, Red = > 1.0 G


Lineal Acceleration (Gs positive = acceleration, negative = braking)

 

GPS Visualizer (http://www.gpsvisualizer.com/map_input) is a tool that can be used with the Lap Timer export file "LapTimerGPSRecDB.csv" to overlay GPS data in google maps, Google Earth, and JPG formats.

LapTimerGPSRecDB.csv: recorded GPS fixes as universal CSV format

Sample Input Screen


Example Output

1. Two best runs compared (same as post above for 5/22/11). Variation in GPS accuracy makes the comparison almost useless.



2. All runs (generated via export all laps for the day from Lap Timer). This really is only good to show the variation due to GPS accuracy.

 

Great info in this thread. Nice driving and very good video Random1

 

I just purchased this chinese $80 version of the Kiwi Wifi. It took about 20 days to get here, but I have verified that it works and syncs with Harry's Laptimer. I get an update rate of about 1.6-1.7Hz. It also syncs with Fuzzycar for your OBD code info.

I look forward to taking some track video with it at the end of the month!

 

Here's two iPhone 4 videos with Harry's Laptimer and OBD data capture. The mount is a bit shaky unfortunately.

First one is a clean lap:

http://www.youtube.com/watch?v=UpyOIXbCb4w

This one shows the importance of taking the right line coming up the blind hill.. got it loose but I saved it.

http://www.youtube.com/watch?v=hWQfKz3pXfA

 

I've been trying to use HLT for autocrossing ever since version 12 was released, but I've only gotten about 3 runs to work (kind of work...). Every other time I've tried using it I just wound up getting nothing (data error, video error, no triggers, incorrect triggers, etc.). Now that HLT has changed the way autocross runs are triggered, I'm having an even harder time with it. When the iPhone 4 is mounted between the roll hoops, you can't easily hit the "Staged" button at the starting line. I tried getting it all setup before getting to the starting line, then just reaching around the phone to hopefully hit the Staged button, but the screen saver must have already kicked in. Do any of you have any suggestions for a workaround?

BTW, I just made a new mount using a Bubo, and I think it's going to work out very well.

 

Sorry, no work around for the mounting position you are using. I have thought about it, but never thought it would work well due to the high level of interaction required to make sure everything is working. In my case I have the WiFi OBDII and external GPS, so must be sure that everything is connected before starting, especially if I take the iPhone out of its mount between runs and walk around with it. I would recommend getting comfortable with using it up on the windshield before trying to use it between the roll hoops. This way you can check things and see what's going on.

At this time I use the iPhone on the windshield and a Drift Innovation HD camera between the roll hoops for that view. The Drift camera has a wireless RF remote for start/stop. Too bad the iPhone does not have a remote of some kind to help your situation.

It's possible that your mount could be affecting the GPS receive capability of the iPhone. An external bluetooth unit mounted on top of the roll hoop would be a better solution. If you get an external GPS you can even carry it on a course walk. I usually put it under my hat.

The primary way that I use the app at this time is to select video at the start line and then press record before taking off. Then at some time after the finish I select stop. Stopping recording when I want is good for catching the announcement of my time or my saying the time after the run so it's captured. There are a couple of other button pushes in there at prompts. Recording in this mode still allows comparison of runs for speed, acceleration, etc. It also provides more context by getting more video before the start and after the finish. This approach is flawless and will never leave you hanging because the start point was not picked up. I appreciate Harry's attempt to make the autocross mode, but I find it too over bearing. I need to provide him some feedback on this.

Give it a try on the windshield and see how it goes. I have had good success with that mounting position and the manual start/stop.