Started this a few years ago, and it's become quite the "ecosystem" of sorts. Originally built for amateur 4t karting, as a general laptimer can work with about anything.
Starting on this I found a dozen projects from other, but not much publicly available code, or the code that was available was extremely basic and couldn't account for a huge number of edue cases so I ended up building my own.
It can handle circuts, and also point2point sprints/autocross
I parted out the actual laptiming to its own library, published as an Arduino library. Manages course detection based on passed sectors and driven distance over the first lap
So anyone can now use a pretty damn reliable timing library with whatever frontend you want to build.
Does actually work on lower end AVRs but with reduced precision
Primarily built around the NRF52840
Tested over a couple of years on a highly technical track where a couple turns come close to the finish line, 1000 different edge cases have been rubbed out
Uses a ublox m10 gps at 25hz
Also has a custom inductive tachometer circuit (schematic on GitHub, tho the docs need an update...)
On-device laptime/optimal time based on splits/predictive pace compared to best lap
I also implimented the insta360 gps remote protocol, so when an engine starts it also boots up the camera and starts recording. Also pairing the GPS data from the logger for viewing after a session.
I also have a bit of a prototype wireless temperature sensor, but I'm not posting that until it's a bit more polished.
Oh... And unlike every other the other similar projects posted over the years, open source, fully, I'm tired of people gatekeeping in the racing industry...
Companion app: race studio on your phone
It was originally built before Claude code, like I said I've spent a few years on this, but yes the robot has put in a lot of work the last few months bringing this to a level of polish
A mychron is now $750 parts for this is about $100-150 depending on what you already have
A smarty cam is $1700, the wireless link to the insta360 offers the same features for .... Just the price of a multi-purpose insta360
Maybe eventually I'll add BLE can support, who knows, but I do know some pretty neopixel LEDs are next
