CAN Signals to Buttons Mapping

Hey everyone,

Is it possible to map the signals received from the CAN bus to button presses?
Okay, let's say that for a specific signal or code, pressing the 'volume up' button triggers an action?

Application example:
Die Lenkradfernbedienung mit PC per CAN mithören und dann lauter bzw leiser zu stellen wenn man auf der Lenkradfernbedienung drückt? ZSure, here is the translation of the text from German to English:

'For example, for a car PC?'

Best regards,

Quote:

Is it possible to map the signals received from the CAN bus to button presses? Okay, let's say that for a specific signal or code, pressing the "volume up" button triggers an action? Application example: Can you listen to the steering wheel remote control via CAN on a PC and then make it louder or quieter when you press a button on the steering wheel remote control? For example, for a car PC?

Basically, yes...
If the steering wheel control unit broadcasts the button presses, it should be relatively simple. However, if the steering wheel doesn't transmit anything until it establishes a communication channel with the radio/navigation system/hands-free system (which is supposed to exist), it's almost impossible without information that is hardly available.

Hey,

Could someone please advise me on which software would be most suitable for this?
And also hardware?

Best regards,

Hello,
You'll have to reveal more for that.
Vehicle, M&F (presumably referring to 'mother and father' or a similar concept), radio.

Based on an A4...
'The signal is routed to ID '5C3' of the Modular Functional Unit (MuFu) on the infotainment CAN bus. You can definitely read this and analyze the CAN frames, and then control external devices or connect anything you want to it.'

With CanHack software and a CAN dongle, you can even identify the ID and collect all the data in advance.

Regards,
Schorsch.

Hey,

Okay, I have a Corsa D with the 'CD 60 NAVI' infotainment system.
Lfb is the usual term, and I don't have any further information about it.

But ultimately, I need something for the 'external interface.'
I was just thinking about a program that would monitor the COM port and then process the incoming commands. Is it really that 'simple'?
However, is it necessary to establish a connection with the CAN-dongle first? Or does it automatically start sending data as soon as it's plugged in?

Hello,
Just to clarify, each vehicle manufacturer has its own infrastructure and uses different IDs, but the CAN specification itself is the same.

Have I understood correctly: you want to press a button/buttons and then essentially feed information into the CAN bus, similar to how a button press on a multifunction steering wheel would normally do?

Okay, I can definitely help you with an A4, but I have no idea about the IDs used in Opel vehicles. That's why I suggested the CAN dongle that allows you to monitor the CAN bus – unfortunately, if your vehicle doesn't have a multifunction steering wheel, you can't use that either.

My construction site is more in the VAG area.

Regards,
Schorsch.

Hey,

I understand the issue with the manufacturer-specific IDs. I would also be able to figure those out through trial and error.

No, I mean the exact opposite.
I want to press a button on the LFB and capture the corresponding data using the CAN-Dongle. I then want to use this data in my PC.

But is a CAN dongle already in 'listening mode' and does it immediately send the data to the COM port? Or do I need to do something else?

Best regards,

Hello,
Okay... so you're pressing a button on the steering wheel remote and want to use this message further in your PC/CARPC.
The CAN dongle is initially just hardware. For example, I use an MHS TinyCAN and read data from the CAN bus using the can tool. In the can tool, I configure the bus frequency, etc., and then establish a connection to the bus. This allows me to read data or even write data to the bus.
Of course, there are also CAN-dongles that come with an API, making them relatively easy to integrate into an application. These dongles are then initialized upon program startup and provide data directly.

That's only half the story. A CAN frame has an ID and can carry up to 8 bytes of data. The message you're looking for might be hidden within one or more of those bytes.
Trial and error... have fun!
For the A4, it's 0x5C3 (2 bytes): 0x39 0x00 (nothing is activated).
If I rotate the left roller, for example, upwards or downwards, only the second byte changes from 0x00 to either 0x02 or 0x0C.

Do you understand what I mean, or have I not explained it clearly enough yet?

Regards,
Schorsch.

Hey,

Yes, that's exactly what I meant. This is how I had it planned:
I repeatedly press the desired button/roller, and I can see in the CANMonitor or a similar tool that the button/roller is pressed multiple times, and the corresponding ID is displayed multiple times.

Best regards,

Hello,
Unfortunately, I've never connected anything like that to a PC before.
The ID essentially functions as an address, and the transported data, up to 8 bytes, represents the data or commands. There are also data packets that operate as multi-messages, meaning that a single ID can trigger a sequence of consecutive transmission cycles.

In the A4, the ID of the multifunction steering wheel is repeated every 500ms. This means that not only is the change detected after pressing a button or turning a dial repeated, but the idle state is also constantly repeated – not just when a change occurs.

Regards,
Schorsch.