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Author Topic: CAN Vehicle Information Display - Should I sniff the CAN bus or request values?  (Read 15965 times)
TRespect
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So It looks like an ELM device is better suited for sniffing.
I thought about buying an FTR232RL cable to use for both nefmoto tools and for sniffing and making the app but I think the elm device is what I need for this project.
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prj
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It's gonna be a hell of a lot easier for you if you are satisfied with the data that is already present on the bus on CAN.
Then you can simply listen to the CAN frames and pick out the relevant data without doing anything.

Communicating with the ECU and requesting is a lot more involved.

Not to mention it will block all other diagnostic communication attempts, if the hardware is permanently installed in the car.
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TRespect
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So the elm device for sniffing and replicating the buttons and the ft232rl for diagnotics.
I can use the elm for reading measure block I guess.

The idea is to have an app which:
Show some info (read some measure blocks)
Replicate button/knob presses and => climate control buttons/knobs mainly as I will replace the headunit with a windows media player style frontend and I won't need the radio button messages.
The Touareg has special steering wheel with access to internal menus. if I can get the same functionnality as the buttons I will replace the steering wheel with a sportier/sexier wheel :-)
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prj
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Then you need some sort of uC devboard.
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TRespect
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can you give some more details please?
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TRespect
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Touareg steering wheel
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TRespect
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I would like to replace it with something like this even without any buttons.

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prj
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can you give some more details please?
If you need more details, then I don't have high hopes of you ever completing this.
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TRespect
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 Smiley

There is always hope :-)
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woj
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ELM can do both CAN and K-line (but beware of the very cheap Chinese clones that have seriously castrated functionality), but you can't do them both at the same time. Also, it can sniff CAN traffic, but e.g. combining this with true diagnostics requests becomes cumbersome. Plus the serial AT protocol gives substantial overheads on communication and programming (I can make it work, it is versatile I agree, but I hate it with all my guts). For K-line a simple KKL based circuit will be sufficient, both for PC and a board of some sort, only needs suitable program coding. For CAN the best results I got so far was Arduino plus a CAN shield, you can actually buy integrated boards for this (see http://www.hobbytronics.co.uk/leonardo-canbus). But in either case, if you plan to do something interesting, you would have to solder a bit and decide and then design what you actually need. Also, proper MCP2515 programming on Arduino handling heavy and fast CAN traffic with multi frames is a PITA, you almost have to write a complete OS with interrupt based ring buffers and what not (I learned it the hard way couple of last months, with a finally perfect result). Another alternative is RaspberryPI with a CAN hat. Here the low level programming is sorted out by good people, yet there are other things to take care of (also went this route).

As an example, the picture (was supposed to, there is a problem with adding the attachment) is a box I made that hooks up to the CAN and to the Zeitronix Zt-2 module over serial at the same time, repackages it all into a new packet which is then sent over BT / another serial to my Android app. Plus it has a couple of ready equipped inputs and outputs for dash buttons and lights. Ideal would be to make a proper integrated board design and make it produced in small quantities, but that's just a proof of concept prototype. You can find a clip in a thread nearby.

So this is essentially the route you are on Wink
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woj
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Let's try the picture again...
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TRespect
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That's hope :-)
Thanks for the details.
What does your app do exactly?
Do you have a website or a blog/thread ?
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woj
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Oh dear, the laziness, three threads down man Wink https://www.youtube.com/watch?v=UJV2sLSf55s

No, no website / blog, had I have time for websites I wouldn't have time for doing these things...
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TRespect
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oh yes I see. I'm gonna take a look :-)
This is gonna be a hell of a project. I intend to keep the Touareg for some time so I will take my time to make the custom carpc with all the obd goodies :-)
So far I have a carpc with a media frontend (DriveLine) and a custom c# phone solution using a bluetooth dev board and a killer mike (https://partners.andreaelectronics.com/da-350-auto-array-microphone/)
BT Phone has always buggered me so I went the dedicated hardware route and bought a BT devboard and an array mike.
I will have to do some shopping for the Tesla-Style Touchscreen solution for the Touareg.

Here is a Tesla Style solution for the Passat. They don't make one for the Touareg.

http://www.suavdvdgps.com/a/Full_Touch_Android_GPS/VW_Series_andoid_GPS/2016/1027/1718.html




« Last Edit: March 12, 2018, 11:28:29 AM by TRespect » Logged
TRespect
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Nice demo there !
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