ECU - New Lap timer
We've added support for lap timing with the latest update to the ECU software.
It's been a month since the ECUs first outing at Snetterton, and back then we tried to record lap times by picking up on magnetic induction using a reed switch. It's how Alfarno karting systems record lap times at kart tracks. Unforutnately it seems that those magnetic coils aren't universal, or at least there aren't any magnets at Snetterton. It might also explain why the Alfarno has never worked since mounting on the Batten3 in 750 Formula. So since Snetterton I've been working on a replacement system which uses GPS co-ordinates to determine when the car has crossed the line. This alternative solution had it's first test at Rockingham this weekend and it seems to work quite well.
The GPS we are using is a cheap UBlox 6 based module with a max update rate of 5Hz. This means we only get a position once every 200ms. So determining the exact time at which we crossed the line requires a little time/distance calculation. The only problematic part is determining the exact co-ordinates of the start finish line. The stewards don't take kindly to folk wandering onto the track, so it has to be estimated from the pit wall. The next thing on my list though is getting two-way comms (telemetery) between the car and the pits, which will mean I'll be able to tell the ECU to record the finish line co-ordinates when Billy goes out for qualifying. That'll take most of guesstimation out of it, and mean that our times should closely coincide with the official timing.
The video below shows one of my test runs during debugging - The GPS is connected, but the water temp, and RPM guages are not. The RPM values you see are being filled in by a dummy test module