Harry's GPS Suite Forum

All,

I have had this program now for a couple of versions and really appreciate the effort and time that Harry has put into the latest release. The Autocross mode is exactly what was missing from the software that kept me from using it. The last time that I ran his software was at my local autocross and had very poor results, before autocross mode was added.

The autocross I choose to participate in is set on an dis used air field. The way the organizers choose to set up said track is with the entrance and exit of the track within about 5-10 meters of each other. My iPhone 4 has decent GPS reception, but most of the time it cannot distinguish correctly when to start and stop. Is there any way to better define my triggers so that they don't overlap. Is it better to do them while driving (parade lap) since the app will know my direction of travel and not just a discrete point in space?

If I can't figure out how to modify the automatic triggers, I am O.K. with manually starting and stopping laps as I am more interested in track maps and logged data than I am lap times.

I am really looking to have this working before this Sunday any suggestions are appreciated.

Thanks,

Chris

Hi Chris,

Please check the triggers, one should be a 'Standing Go' and the other one a 'Stop'. Although I did not test such special cases too much, LapTimer should be able to handle the situation as it ignores Stop triggers while not lapping and ignores Go triggers while lapping.

- Harry

Would it help if he also enters "Direction"?

Directions are currently used for display only. Being more restrictive here would break a lot of track sets currently.

- Harry

Well, A report back from the Autocross:


I ran and used LapTimer with varying degrees of success.

The main problem I found is that no matter how I define the start of the Autocross track (Standing Start) I could never get it to prompt me with the "staged" message so I could initiate the accelerometer based starts.

I kept being too far off in one directon or the other from where the start marshall placed me as compared to the lap timer "thought" I should be. This means I had to start my runs manually, which obviously is distracting and lends itself to accuracy problems.

A few instances I was within 1 meter of the spot that lap timer "thought" I should be in for staging.

Is there a provision for setting the accuracy required for staging? Would you consider adding that as an advanced feature?

Would it be possible to have a start trigger that has no requirement for accuracy before starting, but still triggered at a change in acceleration?

Thanks for taking the time to feild suggestions from users such as myself.

Hi Krispy,

I think I've found the problem. You are using an iPhone's internal GPS, correct? Autocross was tested and optimized with external GPSes... The internal one do not deliver updates / location changes when standing still. Due to an optimization in the code this led to the situation described - no Charge button for standing start. I have fixed this already and will check if it is stable now. I will upload 14.1 afterwards.

Sorry for any inconvenience.

- Harry

Harry,

Yes I was using my iPhone 4 internal GPS antenna.

By the way, there were a few other guys at the race this weekend that used your app too. I know at least one person had success with it while walking the track.

I would be willing to buy an external GPS antenna/ receiver if I could use more than 1hz for my GPS fixes. I just want to make sure I can justify the cost with the somewhat limited amount of track time I am getting these days.

I would be happy to beta test your 14.1 if you like.

Thanks,

Chris

On high update rates: Emprum UltiMate GPS is the choice, it has 5Hz and is Apple certified.
On beta testing: I skip this for minor releases like 14.1 - but thanks a lot for the offer.
I hope I will get it out next week.

- Harry