[MagnusT]

I saw these cool videos with multiple temperature measuring points over the tire width with temperatures varying through corners, chikanes and straights. I thought this info would be a good learning point not only for setting up the car but also for driving style adjustements. But the sensors I found where totally outside of my budget so I did some digging and built this myself instead

For about 100$ per wheel you can build this yourself and it works with both Harry's Laptimer (released) and Racechrono (currently in beta)

It is built on a thermal camera sensor (it's a 4x16 pixel camera where I use the mean value of the two middle rows) and a very nice little armprocessor board with low energy Bluetooth built in.



All info on parts needed and how to put it together is here: https://github.com/MagnusThome/RejsaRubberTrac



Feel free to share this info on other trackday and hobby racing sites. Would be much appreciated to have info about my fun little project spread

[MagnusT]

If you have any questions just ask away :-)

[ZM2]

Looks pretty sweet.

Where do you place the cam sensor so that it is viewing the the the exact same portion of the tire all the time, while you’re steering and the tire is moving thru its suspension travel?

[MagnusT]

From exactly above the top of the front tire will minimize the movement of the tire in the "picture"/measurememt's line but of course not eliminate it. But there are compromises with some angle possible that works pretty well. Currently on my M2 they are mounted much to much at an angle but it still gives an idea how it works. I'm going to move them further towards right above the tire. There's a picture with some comments uploaded on the github page about the thinking on this.

[philisme]

WOW impressive !

Congratulations, I'll try to build it for my M2C.
Where do you install the sensors in the wheel arches ?

[MagnusT]

I found the perfect way to mount the sensors! Perfect location right above the tire. This means minimal tire movement in the sensor's field of view during turning and perfect for measuring distance to tire. The 120 degree angle field of view thermal camera sensor is used, the distance is about 9-10cm when stationary so the full tire width is well inside the FOV.

I made a small 3D printed snap-in holder and just a small hole in the plastic inner fender.

I just open the hood and reach in to remove the sensor from the snap-in holder or turn it on or of.

[MagnusT]

I had some fun (slightly overinspired ;-) track driving on thursday with a friend on the Gelleråsen track :-)

The Gopro mount snapped so I ended up with a sub optimal temporary solution where the camera is mounted way too low, so the view out of the car is really crappy in the video :-(

Interesting to see how temps change in different track sections!

Ps:
No the phone is not in the way of my view at all (since I'm almost 2m tall) but it is really obstructing the view in the video.

[Tano]

Nice feature, looks cool.
What mods do you have and what was the outside air temp? Your Fluid temps look quite high for me. I have never got this high oil and water temps even on days with 30+C air temp. For ex. on my last trackday it was 34C outside and my max oil temp was 115C and water was 108. How did you reached 20C more?

[MagnusT]

Yeah surprisingly high. No mods. And it was between 25 and 30 degrees only.