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RejsaRubberTrac
Would it be possible to add two more sensors to the board?
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Här sen Apr 2023
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I would like to add oil temp and oil pressure sensors from the closest RejsaRubber board.
Would it be difficult to read them as a sensors in Race Chrono, or will it need work by the developer?

I've had a look at the code, but it's over my paygrade at the moment. I'm willing to spend more time learning how to make it work if it can be done.

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Bernhard Benum
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Magnus Thomé
Stockholm
Här sen Nov 2002
Inlägg: 41507

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BB skrev:
I would like to add oil temp and oil pressure sensors from the closest RejsaRubber board.
Would it be difficult to read them as a sensors in Race Chrono, or will it need work by the developer?

I've had a look at the code, but it's over my paygrade at the moment. I'm willing to spend more time learning how to make it work if it can be done.


That would necessitate a substantial rewrite in Racechrono / Harry's.

You could fake it and insert oil temp and pressure in place of two tire temperature readings of course, but wow that would be an ugly way of doing it


Just add another ESP or nRF MCU board and use the API Racechrono has published for picking up any sensor data over BLE, check the Racechrono forum for links to this thumbs up

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Magnus Thomé
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Här sen Apr 2023
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Thanks for saving me a lot of time.

As far as I can understand the maximum number of simultaneously connected BT devices is seven and I would like to run these:

OBD2 ( but without oil temp/pressure information)
GPS
4 x RejsaRubber
I don't remember if my GoPro camera is controlled via Wi-Fi or BT.

I'm going to buy a tablet. Will I need a very fast tablet to cope with this many connections?

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Bernhard Benum
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Magnus Thomé
Stockholm
Här sen Nov 2002
Inlägg: 41507

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To be honest I don't have a good feel of what is needed to run Racechrono with many Bluetooth data sources, sorry.

Another way could be to insert oil temp and pressure data as CAN messages to the OBD2 dongle although it could mean having to do some trickery not to clash with the car's original data. But totally doable.

Or you could completely replace the OBD2 dongle with the Racechrono DIY I mentioned earlier.

Either way would take some coding of course.

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Magnus Thomé
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Här sen Apr 2023
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I'll see what I can come up with in time.

Thanks for making and sharing the ResjaRubberTrack project and for taking the time to respond.

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Bernhard Benum
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i96danma
Enebyberg/Danderyd/Stockholm
Här sen Okt 2013
Inlägg: 621



Bernhard, I don't know if you're aware but BLE (Bluetooth Low Energy) is a slightly different beast from regular BT. BT has a limit regarding "slave" stations but BLE is structured in another way and does not have such a limitation. I see no reason (except deliberate or unfortunate restrictions in software) why you wouldn't be able to use an arbitrary amount of sensors.

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Dan Mattsson
981 GT4
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Magnus Thomé
Stockholm
Här sen Nov 2002
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It's more about the bandwidth of incoming data. But I really don't know what the limits are with today's mobile phones (and the Racechrono code). And more importantly where the main bottlenecks are.

In the sense of bytes per second it is miniscule but even getting all tire data over at 10Hz was tough with the BLE setup I used. But no problems having four tires doing it simultaneously. Again, I have no real idea where you'll hit some bottlenecks.

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Magnus Thomé
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i96danma
Enebyberg/Danderyd/Stockholm
Här sen Okt 2013
Inlägg: 621



Yeah, bandwidth is an issue but not all sensors need 10 or even 1 Hz.

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Dan Mattsson
981 GT4
Citera
RejsaRubberTrac
Would it be possible to add two more sensors to the board?
239 besök totalt
Tack till alla våra trogna sponsorer som stöttar och håller Rejsa rullande