Tyre temp monitors

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Re: Tyre temp monitors

Postby Talkiet » Fri Sep 08, 2017 10:52 pm

Talkiet wrote:
techtoys wrote:I'm working on a similar system at the moment too. Sensors are Adafruit Contact-less Infrared Thermopile Sensor Breakout (TMP007). The device that polls them will probably be a 4Duino because of its built-in display. The trickiest part will probably be working out the CAN-bus messages to send from the 4Duino to the AIMsport datalogger system on the target vehicle.

We want the tyre temperature data to be integrated with lateral G-forces, track position, speed, steering angle, and suspension position. Otherwise it is of only limited use.

From experience with my own car, tyre temperature measurement after the cooling-down lap at the end of a race is meaningless.


Cool, this is very close to what I am doing - except I am not looking to integrate into a legit datalogger. I'll probably include a GPS module on my build and log with time and location stamps and then process on a PC afterwards or parse into something that racerender can use. Good point about the other inputs being needed - some of that can be derived from GPS but with a suitable i2c multiplexor solution we should be able to grab as much as we want.

Cheers - N


Well, the parts have turned up and if I wasn't competing all weekend AND shifting house in the evenings I'd be able to knock out a one wheel proof of concept tomorrow. I expect to have a working version next week sometime.

I made 2 mistakes in ordering (which fortunately are pretty cheap mistakes on Aliexpress)... I ordered the cheapest sensor which turns out to have a 90 degree Field of View... I'll need some narrower FOV parts to do it properly, but these 90degree parts will work fine for proof of concet. The second mistake was ordering i2c multiplexors - even though all the sensors have the same address out of the factory, they can be reprogrammed, so wiring them all up to a single Arduino just became trivial!
Cheers - N
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Re: Tyre temp monitors

Postby Talkiet » Fri Sep 15, 2017 6:25 pm



Sorry for the vertical filming - it was the easiest way to get the exposure for the screen right as well as being able to see the sensors.

This is about $35 worth of parts, although there is a smaller Arduino board I have which would bring it down to about $25 worth of parts. However this also uses the wrong IR sensors - these have a 90 degree field of view. The correct ones with a much narrower view are quite a bit more expensive - about 2-3 times the price of this model I have used for proof of concept.

Next thing I'll get a screen rigged up to display the numbers - or possibly make each wheel completely self contained with it's own arduino and have all 4 wheels report to a smartphone on the dash... That way there would be no wires to run anywhere if you were prepared to run each corner on a battery.

Looks like it'll work well. The update speed is artificially slow here - should be able to get easily 10Hz .

Cheers - N
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Re: Tyre temp monitors

Postby Talkiet » Wed Sep 20, 2017 7:44 pm

Small update...



Have a screen working for standalone operation

Have ordered
- Correct 35 degree FOV sensors for 4 wheels
- RJ45 breakout board to connect all 4 wheels to single Arduino
- 3 different size screens to test
- RJ45 connectors for each wheel set

Still to order
- GPS module for time sync and location info
- SD card interface for logging
- sensors for detecting Gforces (breaking and cornering)

This SHOULD result in a display/main unit with live display of tyre temps brake disc temps - and logging of all temps plus timestamp, location stamp and G-forces on car at that moment.

I can probably get the display to include speed as well but I don't want to go down the path of writing my own lap timer.

In fact if there's a good lap timer that can accept realtime inputs (for the tyre and brake temps) to include in it's datastream, I'd love to know about it...

Cheers - N
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Re: Tyre temp monitors

Postby nz_climber » Thu Sep 21, 2017 8:07 am

Nice, you seem to be making good progress, can you put up links to the new sensors you are getting?

Racechrono can accept external logging inputs via Bluetooth data stream, just needs to look up their message format

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Re: Tyre temp monitors

Postby Talkiet » Mon Oct 16, 2017 8:18 pm

The good sensors have arrived, as has one of the GPS units. Both of those are tested and working great.

The CanBUS shield has arrived but like an idiot I only got one of them so can't test it... I also have a couple of choices for SD card use for logging. With the GPS I'll be able to log position and accurate time, so getting the data into a format for visualisation or video overlays later will be easy. Although the emissivity of brake discs isn't ideal, mounting a sensor for the brake disc temp is so easy it would be a crime not to do that as well.

I have ordered some custom PCBs for the wheel sensors, and when they arrive in a week or so I'll be able to assemble the first set to fit to my car. At that stage it'll probably only be a 20*4 LCD display without logging, although I might get GPS for speed on the display.

Of course it's costing more than expected - I didn't expect to get PCBs made but I don't think anything else would survive without being shaken to bits. These may yet be too fragile and I might end up having to encase the whole wheel mounted assembly in epoxy.

Cheers - N
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Re: Tyre temp monitors

Postby Talkiet » Mon Oct 16, 2017 8:20 pm

https://www.digikey.co.nz/product-detai ... ND/3641019

They are the sensors I am getting, although mounted on a board already with the appropriate resistors for easy use with Arduino I2C bus.
Cheers - N
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Re: Tyre temp monitors

Postby Talkiet » Tue Oct 24, 2017 2:07 pm

Working on the sensor side and getting something sorted so they can actually be mounted on the car. Here's where I am at...



Currently the webpage just refreshes every second to pickup new readings from the arduino - there are cleverer ways to do it but this was just so I could see the data. I'll probably spin up another board which will be able to have the sensors, arduino and battery (plus switch) so it can be a complete standalone unit that can be ziptied to a mount for each wheel. The display will be a phone on the dash with a better method of showing all the wheels.

Oh, there's a spare header on the board (currently used to connect to arduino) that will have a sensor for the brake disc.

Cheers - N
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Re: Tyre temp monitors

Postby nz_climber » Wed Oct 25, 2017 10:16 am

Very cool progress. Makes me wish I had time to work on my dash project.

Keep up the good work, what software and company did you use for designing and producing those pcb's?
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Re: Tyre temp monitors

Postby 7ish » Wed Oct 25, 2017 10:18 am

Looks good, Neil. Might be a market for such a thing??
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Re: Tyre temp monitors

Postby Talkiet » Wed Oct 25, 2017 11:43 am

Thanks guys... I used easyeda.com for the deisgn and production of the PCBs and wholeheartedly recommend them. It's an entirely web based app and I went from knowing NOTHING about PCB design (except that they existed) to having designed and ordered the PCBs in about 2 hours.

I think I'll spin up a new design after it's all working integrating everything together on a single board (for the brains/gps/logging/canbus/screen interface). It's way way easier than I thought and even soldering onto the PCBs took very little practice.

There might be a market for it. I have posted on Facebook in a group (RCIS - Race Cars In Sheds) and there's a heap of interest plus several people offering help with enclosure design and production etc... The alternatives in the market now seem to start at over $2k and seem to require a digital dash of various brand names... The component cost of mine will be low, but the tooling/time/ancilliaries like good connectors etc will bring the price up. I still see it being EASILY under $750 for a set, possibly quite a bit lower if I can get someone else to help with the enclosure CNC design and production.

I won't be thinking too hard about selling through until I have it working pretty well on my car (and perhaps other local guinea pigs)...

Cheers - N
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