Originally Posted by wstar

Neat! I'm a software developer too, but in a completely different area. I'm not an iPhone user, but if I could offer a feature suggestion for your app: I've found the predictive lap times on my current datalogger setup *really* helpful. It's a mode where, as you go around the track, the display shows a prediction of what your lap time will be (based on your lap time-vs-position compared to other laps), and gives a display something like:

1:20.44 (predicted full time for current lap-in-progress, which varies up and down)
+0:03.44 (prediction above is 3.44 seconds slower than your best)
(and then red/green background for whether the current prediction is running faster or slower than best)

The predictions tend to be a little jumpy at the start of a lap and then settle in the closer you get to the end, obviously.

When you get the hang of watching that out of the corner of your eye, you start picking up mid-lap info like "hey when I missed my turn-in back there, it set me back 0.3s on my laptime", or "yeah, apexing this spot a little earlier saved me 0.2s".