RE: MSR Cresson, Tx. May 15 & 16

2010-05-19T04:44:31Z

Thanks for the feedback. Depending on the phone (Eris, Droid, Nexus 1, Magic, etc), you'll find the GPS and accelerometer accuracy to vary slightly. The bluetooth GPS does makes a world of difference in the results.

Jeff

MSR Cresson, Tx. May 15 & 16

2010-05-19T03:52:25Z

I got the 2.1 upgrade for my Eris Sunday morning, so I downloaded Trackmaster and used it for three HPDE session on Sunday. The lap times seem very accurate based on folks I was running with and an onlooker with a stop watch. However, the finer data seems pretty lacking in accuracy. I suppose its the 1 Hz max GPS sampling rate of the phone. I'd love to get a external bluetooth GPS, but the phone does not support the SPP profile.

There are a bunch of zeros in the speed, acceleration, and bearing columns of the spreadsheet.

My best lap had the second lowest average speed. I think that is due to the length of the lap changing.

The lateral and braking Gs look reasonable, but a MINI can't generate over a G of acceleration. Probably not half a G.

And the track overlay has some big discrepancies.

I'm not bringing this up to complain. I'm hoping there are suggestions on how I can improve these items. As I said above an external GPS is not possible.

And even if I only use it as a lap timer its worth the price.