New Lap Timer

Frustrated with the lack of reliability and predictability of the Sumomoto GPS integrated lap timer I decided to invest in a Qstrarz Extreme 10Hz GPS and an application on my smart phone called RaceChrono for collecting the data. The perceived advantages are that these products are more predictable, reliable and less time consuming to illustrate the results.

Predictable: In that if I kick off the RaceChrono (on my smart phone) and it looses the whole sessions data then the GPS memory will still hold a record of the tracks (42hours worth).

Reliable: The GPS has a more sophisticated receiver that is less likely to loose lock (Adopt MTK II latest chipset with high sensitivity - 65dBm and  66-Channel tracking).

Less Time consuming: The results can be directly imported into RaceRender the visualisation software.

The disadvantages are 1) The GPS has to be mounted away from my roll-over bar for best reception as it has no remote aerial 2) The lap times have to be computed for the likes of Kames.

The first problem to solve was the waterproofing and location of the device away from the cage for best reception. I did this by mounting it in a dummy camera box (see pictures).

The second issue is to program RaceChrono to adopt a track, that is known to me and where I can do some testing on. I decided to use the Kames test day on 31st Aug 2014.

The problem with sprints is the track is not a simple circuit. It starts with a run up area to the first hairpin and does two and a half loops then has a run down area towards the paddock turnoff. I decided to nominate several split points so I could maximise the information from the trail runs.

* Start point
* First hairpin
* Finish bend
* Paddock bend
* Paddock exit

The first lap progresses from the start point to the first hairpin, then to the Finish bend, down to the paddock bend, then back towards the first hairpin, then back towards the Finish bend.

Then it repeats on a second loop missing out the Start point, then a third loop finishing at the Finish bend.

Track input

The problem with all this is that RaceChrono knows nothing about the Kames unique 2 1/2 laps that constitute the competitive track.

GPS disguised as a camera

GPS exposed

 

Timing analysis by data points and position on track

confusing split times.

 Competition type result analysis.

The above split times are of minimal use as the smart phone app does not know the shape of the real track with it's 2 -1/2 laps. However using the Timing analysis you can reconstruct a real lap time.

A lot of discussion in the paddock took place as to what time my car was actually doing in a conventional type lap situation. I have taken that to mean Finish bend to Finish Bend. From the above data extracted from the Timing analysis screen (resolved to 0.1s) that can be shown to be approx. 33s. Later attempts by me I suspect were faster but I did not measure them. In addition the afternoon session was given over to passenger rides.

The key number is in the bottom rhs as this equates to a real lap time.

The data can be imported to RaceRender: http://youtu.be/Z9s3z83nGKU

Enjoy!