Lap Timer doesn't tell you when it's making a mess

Help on issues you run into with LapTimer; in case you have a question on how to use LapTimer, use the forum "Using LapTimer" instead
Post Reply
astrayelmgod
Fewer than 10 Posts
Fewer than 10 Posts
Posts: 3
Joined: Sun Mar 25, 2018 4:59 pm

Lap Timer doesn't tell you when it's making a mess

Post by astrayelmgod »

I have Lap Timer on an iPhone. I use it for autocross only, no track racing. LT works OK when it works, but my complaint is that it still pretends to be working when in fact it isn't doing anything. Take yesterday for example. I was at an event at a location where I have competed before, and gotten useful results with LT, so I know it works, and that I know the basics. I set it up as before, walking to the start and finish lines and pressing the proper buttons. At the end of setup, it said Drive! as usual. I did, and it went to the Staging screen, and then Staged as usual. I pressed the Staged button when I was at the line. When I started driving, there was a Bing! and the timer started.

At the end of the day, I had... nothing. Not a speck of data from a single run. The only clue that I was even there are the GPS coordinates from the start and finish lines. This is really disappointing to me as I tried several techniques that should have been faster, and they ranged from no difference, to actually slower. With no data, I haven't a clue about what happened.

One clue is that LT has trouble with different events that are close to, but not in the exact same space as previous events, as autocross always is.

Can you please add a screen that says, "Sorry, nobody is home and despite what it looks like, nothing is going on"?
User avatar
Harry
Site Admin
Site Admin
Posts: 10518
Joined: Sun Sep 12, 2010 10:32 am
Location: Siegum, Germany
Contact:

Re: Lap Timer doesn't tell you when it's making a mess

Post by Harry »

There are exactly two possible reasons LapTimer does not finish laps: problems with GPS reception, and problems with track sets (misplaced or conflicting triggers). The later can occur in case you define two conflicting track sets in the same space. In this case, LapTimer will show a warning telling you you have conflicting track sets and this conflict needs to be resolved. For the standard AX situation, go to your old AX in Lap List, and swipe delete (or, for Android, long press) the row showing POIs and Triggers. This will remove triggers for this old AX and remove the conflict. Laps recorded will stay untouched.

- Harry
Image Image Image Image
astrayelmgod
Fewer than 10 Posts
Fewer than 10 Posts
Posts: 3
Joined: Sun Mar 25, 2018 4:59 pm

Re: Lap Timer doesn't tell you when it's making a mess

Post by astrayelmgod »

OK, I solved that problem by purging all old date before the next event. Thank you very much for your help.

There are two other problems.

The most serious is that the lap timer doesn't know where the end of the course is. Take yesterday as an example. I set the start and finish coordinates as directed. After the event, I was able to use Google Earth and HLT's Points of Interest in Set to verify that the start and finish were both set exactly right. This would be easier to explain if I could post a picture of the track and the HLT data set (which I have, but don't see how to post), but here goes anyway. The track started on the left side, ran around a big oval, ran out the right side, circled around and finished on top of the loop. The problem is that HLT thought the track was done on the first pass through the loop, which was in fact about 1/3 of the total. This point was about 140 feet away from the true finish line. I was using an external GPS at 10 Hz. All of those points are accounted for.

The second example was a couple weeks ago at a different track. The problem there was that HLT didn't stop timing at the end of the run. I shut if off manually, and as I am more interested in the segment data rather than overall time, I wasn't bothered by it.

The second problem is that the change of elevation numbers are ridiculous. HLT claims that yesterday's course had 20 feet of elevation change. It's a retired airport runway; there isn't any change of elevation. I noticed the same thing in testing around here; HLT claims there is 10 feet of elevation change around my block, which its manifestly not right. I don't really care about elevation change; it's just odd.

Any suggestions? I have a PDF of yesterday's track map, and the HLT data for both events mentioned above. I don't know how to post it or attach it or send it to...?

Best Regards
Gary Olmstead
Ventura CA
User avatar
Harry
Site Admin
Site Admin
Posts: 10518
Joined: Sun Sep 12, 2010 10:32 am
Location: Siegum, Germany
Contact:

Re: Lap Timer doesn't tell you when it's making a mess

Post by Harry »

In case LapTimer doesn’t stop when passing the trigger, there is a problem with GPS accuracy (including dropped connections to external devices), the trigger is misplaced, or the direction is wrong (mostly the opposite direction).

In case you are not interested in elevation, please ignoree it. It has no influence on anything related to timing etc. Elevation measurements are less accurate by a magnitude compared to position data. That’s a characteristic of GPS.

Harry
Image Image Image Image
astrayelmgod
Fewer than 10 Posts
Fewer than 10 Posts
Posts: 3
Joined: Sun Mar 25, 2018 4:59 pm

Re: Lap Timer doesn't tell you when it's making a mess

Post by astrayelmgod »

Well, in the first case, where HLT was shutting off 1/3 of the way through the lap, it was definitely facing the right way. Those two parts of the course were parallel to each other, and the car was going the same way on both segments, but the two segments were offset by 140 feet.
User avatar
Harry
Site Admin
Site Admin
Posts: 10518
Joined: Sun Sep 12, 2010 10:32 am
Location: Siegum, Germany
Contact:

Re: Lap Timer doesn't tell you when it's making a mess

Post by Harry »

Please send your data to Harry@gps-laptimer.de and I will have a look into it.

- Harry
Image Image Image Image
Post Reply