Harry's GPS Suite Forum

Hi Harry

I used my lap timer pro at the track the other day and didnt have much luck. I have an iphone 4gs and I ride a motorcycle at Eastern Creek Australia. It recorded two laps in one session total. I rode about five sessions, four of them giving nothing.

First off here is the low down:

1) I have to put my iphone in my top jacket pocket, timing devices are not permitted at the track, so I have to be a bit secretive about it.
2) GPS reception was green, 3D + lots of satellites. Tested and confirmed with my body in the way (replicating being in my pocket)
3) I loaded the track and then just pressed 'start driving'
4) I then have to queue up and wait in line to get on the track. Some times for about *five* minutes.

Most of the time I was getting a calibration error message, I forget what. It was most annoying. Im really only interested in my lap times, and not how many g's i pull in a corner. Can I just switch this off so i dont get the error message?

I was thinking perhaps there is a time-out while I am waiting in the line out. Perhaps this is due to the iphone screen lock? Does this interfear?

Ideally I would like to hit the start driving button when I get going, but as I said I have to wait.

Hope the above is clear and maybe you have some suggestions?

Many thanks
Ed.

Hi Ed,

Sorry to hear. However, the issues are well prepared I'm sure, if you look into your 2 laps recorded, you will see pretty bad accuracy (use Lap List -> Lap Details -> Data Recording -> select the blue bubbles from the Tool item to show accuracy).

You must not use LapTimer in your pocket, that definitively does not work. There are several reasons: first of all any jacket degrades GPS reception to a level LT has no chance to work. LT relies heavily on good GPS accuracy so that is not an option. Secondly, you have no control on what functions are triggered when moving (includes calibration issues).

There are basically two options you have on a bike: either you mount the iPhone to your steering rod / behind the windshield, or you place it somewhere else (below your seat or where ever you have a save place), and connect an external GPS like the Dual XGPS to get the GPS position.

- Harry

P.S. The waiting time is not an issue.

I cant seem to find the accuracy from the place you mentioned??? Looking at the fixes on the two laps I got about 170 odd over 4.5km.

If I can run my iphone gps sitting in my car, I dont understand why it wont work in my top pocket. Also I leant over the phone purposely to test the signal and it seemed fine.

Anyway, will try and think of a better mounting option.

Thanks for your help.
Ed.

Also I hit the lock button before putting it in my pocket. This is to stop me pressing any buttons by mistake.

I was just reading about the sleep function, perhaps I should try that.

Ed.

Here is a more comprehensive step by step: Lap List -> press one of the two laps -> Lap Details -> Data Recording / Preview -> press the small wrench in the top left -> select the blue bubbles from the configuration hover view to show accuracy (the third item, just above Export).

On accuracy in jackets: it seems to be a different thing leaning over an iPhone and wearing it near your body / in the jacket. I had numerous cases like this, you may search the forum to find some of them.

- Harry

OK Harry thanks for your time. I will fashion some sort of mount under my pillion seat. Hollow it out or something.

No more jacket pocket!

Appreciate the feedback.
Ed.