Wednesday, March 11, 2009

Powertap raw data format change

Powertap's gone ANT+ Sport. So when I sent Saris my previous head unit for replacement when it magically stopped functioning, they send me one with ANT+ Sport enabled firmware. All good: the firmware is still compatible with old hubs. But when I cranked up my venerable GoldenCheetah ptdl and ptunpk command line utilities to download and decode the data, they spit it back out. Saris had changed the "raw" file format.

GoldenCheetahI reported this to the GoldenCheetah user's list. Curiously, my report was the same day Ned Harding reported the same problem (this time in the context of a Windows version of the code. Windows is a virus my system doesn't have: I run Ubuntu 8.10. One month until 9.04! Hold you're breath. There's always issues with "upgrades".). The same day, Ned was able to reverse engineer the new binary format, and posted a patch. Wow. I consider myself a coding hack, but when guys who really know what they're doing show their stuff, I am impressed.

Anyway, I should be able to examine my Menlo Park data within a few days. Yeah, there's Saris PowerAgent, but it won't run in the presence of USB drivers required by GoldenCheetah. And PowerAgent has some really poor features, like plots with severely decimated data and a data merging algorithm which splices active time segments as if inactive time segments had never occurred (two hard 5 minute efforts separated by a minute of rest is not the same as a single 10 minute effort). Anyway, I prefer my own Perl scripts for doing my number crunching. And the GoldenCheetah command line utilities allow me to script without any sticky GUIs.

GoldenCheetah also has a GUI, of course. Actually, my favored command line utilities have been omitted from releases since 210, so I have some work to do porting the patch back to that version. I'm at least good enough for that, though. But for my purpose, the GUI still has a way to go, especially its handling of multiple workouts in a single download. But it's definitely worth checking out if you're weighted down with PowerAgent, especially if you're on a non-Windoze system.

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