I took up riding track days about a year ago, and have been working on improving my skills. Part of that improvement is knowing if I actually am getting faster, and if so, why?
. This little Android app uses GPS to log your laps. Not just lap times, but your position and speed at all times while you're riding. This lets you compare across laps... for example, you might try a different line through a turn, and then see how that affected your exit speed.
You split your track into sections, using split markers. The app will show you your times and speeds for each section of each lap, and produce a theoretical best lap time (i.e. if you rode a lap where you hit your best time for each section, your best time would be X).
The interface for viewing your laps uses a Google Maps backdrop, and displays your line with green when you are accelerating, and red when decelerating. You can click any point on the map to see your speed and elapsed time to that point.
And the beauty of it all is that you can look at all this trackside, between sessions.
The data is synced to the TrackMaster website for storage and sharing
. I took these screenshots from my Android tablet. The data syncs from my phone to the web, and then down to my tablet.
TrackMaster does a nice job of interpolating lap times between GPS points, so if will best-guess the exact millisecond that you crossed the finish line based on the GPS readings before and after the finish line. The in-built GPS of phones takes readings at 1Hz (once per second). This is a little low for really accurate lap times, and really accurate arcs through tight corners. TrackMaster lets you tie a bluetooth GPS to your phone. The external GPS will be more accurate than your phone's GPS, and will take readings at 5Hz or 10Hz (5 or 10 times per second). My phone is old and slow, so I have my GPS set to 5Hz, so it won't have any issues keeping up.
My GPS is a QStarz BT818XT, which has a switch to read at 1Hz or 10Hz. I reconfigured it using the software to read at 5Hz instead of 1Hz.
Costs: TrackMaster is $6 from the Google Play store. You be lappin', mon. You wanna get all hardcore and buy an external GPS? Mine was something like $80. The TrackMaster add-on to use Bluetooth GPS is $4.
For mounting on a Daytona, I put my phone into a little neoprene camera case, and stick it into the cubbyhole under the seat. You could stick into a pocket or something if you wanted, gotta love Bluetooth. I have the GPS velcro-mounted in the tail section, on the plastic bit where the "tool kit" (read: screwdriver) was until you bought the bike, saw it, laughed, and threw it in the trash. GPS Pro-Tip: a decent GPS does not need to be exposed to the sky, it just shouldn't have steel between it and the sky. A thin bit of plastic or fibreglass is no problem. Keep in mind that if you don't use a Bluetooth GPS, your phone will have to be mounted where it gets a decent GPS signal. The GPS battery easily lasts a day, probably a weekend, so turning it on and putting the tail section over it doesn't pose any inconvenience.
Issues: I've only found one issue: the synchronisation to the web can be flaky, and I actually lost some data once. There is an easy solution: back up your session at the end of the day.
That's about it. Got ?'s, I'll try to answer.