Cheap TPMS-to-RaceChrono bridge

MagnusThome

Work in progress but it is up and running: https://github.com/MagnusThome/TPMS-to-RaceChrono

chiller

This is awesome! Going to see if I can get a hold of a few to test.

aol

Nice, well done! :blush:

MagnusThome

I've tested it "on track" now, worked great.

DrMotor

This TPMS-to-RaceChrono bridge works (thank you MagnusThomé, nice work!), but can the same task be done without the ESP32? I mean: The phone already has BLE-connectivity and computational power, so why do we need an ESP32 to translate and forward the TPMS messages? Can we enable RaceChrono to read TPMS directly? ...or can we write an Android app to handle/translate TPMS and forward the results to RaceChrono?

aol

@DrMotor I guess I would need to add the direct TPMS support to RC, for that to be possible

nbdnnm

A phone's BLE connections are not unlimited. So, if there are many sensors, having an aggregator send all of them to RaceChrono makes sense.

DrMotor

nbdnnm About limited Bluetooth connections: TPMS typically uses one single connection to manage all sensors. If the phone is limited to 5 connections, then you can have TPMS + GPS + CAN/OBD + HRM, and still one spare.

nbdnnm

@MagnusThome, have you thought about some high-frequency TPMS? I was looking for pressure sensors that read hundreds of times per second, but their working temperature is usually up to 85 °C. Would be good to make such DIY device :smile:

MagnusThome

This data changes slowly, why are you looking for high frequency updates of this?

nbdnnm

because the most interesting thing is happening in turns The higher the slip angle - the more friction on the tyres - the higher temperature - the more pressure increases also the more friction - more tyre wear so if an average pressure in tyres is ok, it doesn't mean it is optimal in exact time un the turn and right after at least I am curios to check this :smile:

MagnusThome

With my Rejsarubbertrac or others thermal cameras you can see these fast temperature changes on the tire surface. But measuring with a tpms sensor mounted on the tire stem, at that location the temperature varies very slow. And pressure changes pretty slow also of course.

nbdnnm

how often does your tpms gather and send the data?

MagnusThome

Dont know but they seem to send when they detect a change. They are really cheap ones from Aliexpress. There are faster ones to buy if one wants https://team-plus.com/product/tyre-pressure-monitors-tpms-track/

nbdnnm

the one from Ali I am not sure if they are very frequent the second looks very good, thanks!