I thought I would share this with you lot as there is alot of people out there interested in circuit racing and the like.

I have been considering getting a lap timing system for when my car is up and running.. Inspired by Jesters nokia app I did abit of googling and found this little app

http://www.firstclass.com/~ron/Lap_Timer/Main.html

Now as far as apps go its not cheap @ 15 bucks but its a damn sight cheaper than a lap timing system or performance box.. and seems to provide a lot of information..

Now I downloaded Version 1.0 from the app store and it has a few problems like not being able to get the data out of the phone being the main one.

I emailed the developer who has been working on the fix for the issue and also some upgrades. As a result I have been added to the list of beta testers for the new release.

Here is some correspondence between myself and the developer

Changes Since 1.0.2:

1) Added support to pick data files from the View Data screen.
When a data file is picked it can be:
Viewed.
Deleted.
Emailed (requires iPhone OS. 3.0 or above) Useful for import into LapViewer.

Changes Since 1.0.1:

1) Added a display of the GPS frequency and accuracy on the main screen (off by default)
When displayed in red the accuracy is above 50 meters
When displayed in yellow the accuracy is between 20 and 50 meters
When displayed in green the accuracy is less than 20 meters

2) Added a display of the number of meters you are from the start finish location (off by default)

(Both of these are turned on in the info screen)

3) Moved the accuracy display on the "Set Start Finsih Screen" so it can be seen updating when the GPS is fixing

4) Fixed a bug that did not remove the "GPS locating start finish" dialog after the location had been determined.



There are some new features and changes from the 1.0 version and they are:

1) There is an info button now on the main screen to do setup that includes.
a) Calibration of the accelerometer. Place the phone in the installed location in the vehicle and touch Calibrate.
b) Lap Sensor Algorithm. The old algorithm was Circle-Line. (I want to know which one works best for you)
c) Lap Sensor Sensitivity. A slider setting that lets you set the speed at which you will be passing the start finish. (please let me know which setting works best)


2) A manual stup for setting the start finish line
a) You can type in the latitude and longitude of the start finish location or use the GPS to set it.
b) You can type in the Direction (in true north) that the vehicle will be heading when it crosses the start finish line.
c) Using a 3GS you can use the built in compass to set the direction. (the back of the phone as it would be installed in the car so you can see the display is the directional pointer)
d) You can give the Location a name.
e) Once you have saved a location you can pick it or others from a list using "Pick SF".
f) You can test the accuracy of the start finish location after you have moved using the "Test SF" button.

Now I installed the beta to my phone today and had a fiddle..

I emailed myself some data.. and put it into lap viewer.. I have uploaded some pics.. Not much different to whats on the website but at least its real data..

Image 1 Shows the track I took


Image 2 Altitude (from here on in its 2 "laps" overlaid)


Image 3 Lateral G's


Image 4 Transverse G's


Image 5 Speed


Image 6 All of the above apart from track


Now I am not sure how accurate the data is However so far so good I have tested it a couple of times and I used my start point next to a lamp pole so I had a reference point and it reset at the same point every time. Next is to go round a loop at a set speed and see how close the lap times are.. Im sure its not as good as a performance box or a genuine lap timer system but its also a fraction of the price.

I will test it more and keep you informed

__________________
I used to tune cars with screwdrivers.
Clutch, Brake, Accelerate.