CAN Bus Controller: Build Your Own!

Hello CANhack members.

I'm new and have absolutely no experience with CAN bus systems, and I hope you can help me.

About me:
I am 25 years old, a qualified electrician by profession, and I have experience in programming, general electronics, and the manufacturing of circuit boards.

Regarding my issue:
I have an Opel Frontera B, manufactured in 2002. The vehicle's display shows me various messages, such as "left rear brake light defective" or "coolant level too low."
These messages can be scrolled through and confirmed via a control panel on the radio.
Now, I want to install a different radio that is no longer connected to the CAN bus.
Okay, so I need a small rotary knob, along with a circuit board, etc., to control the car's menu system.

Does anyone have any ideas? Has anyone done something like this before?

Thank you in advance.
Best regards, Flo.

Hello Flo,

First, you should check whether the rotary knob is actually connected to the radio and the CAN bus.

If yes: Connect the CAN interface to the corresponding bus, select the "Message Changes" view in KCANMonitor, and turn the knob.
Then you can see which messages are being transmitted on the bus and reproduce them.

Best regards, Rainer.

Hello Rainer,
Thank you for the quick response.
I have a CANBus-enabled OBD2 adapter. Would I just need the software, or does it only work with the set you suggested?
If I know what data I need to send, how can I reproduce or recreate that data?
Best regards, Flo.

Strom_Flo wrote:

I have experience with programming, general electronics, and the manufacturing of printed circuit boards

.
Too bad, it seems not.

Quote:

I am new and completely inexperienced when it comes to CAN Bus systems.

Unfortunately, my experience is limited to the industrial sector.
S7 and Profibus. I don't know how that relates to CANBus.
Best regards, Florian.

What (original) radio and display are installed?

So, the radio is a Siemens NDR 1100.
I don't know about the display. I would need to take it apart first to find out.
Merry Christmas.
Best regards, Flo.

Color display, so I guess it's CID!? So, if it's like in my Astra G (also with NCDR1100+CID), then the display won't even turn on without the radio, no tricks. That's a bit more complex, especially if it's your first project in that area. I have experience with this combination, because my Astra is supposed to work without the original radio .

Hello shavenne,
Thank you for the response.
Yes, it looks like mine. I thought the display was connected to the Msg unit, and the radio was just for control.
How did you manage to separate them?
What should I pay attention to?
Merry Christmas.
Best regards, Flo.

It's better late than never,

Okay, I managed to get the display to turn on without the radio, but I'm probably sending a much stronger signal than necessary, which likely means I'm also transmitting a lot of unnecessary noise.
I can only tell you which IDs you need to listen to and transmit on, and those would be:

6A6 and 6A1: This originates from the display, and here you need to respond to various messages directed towards 6A1.
290: Then, the button presses from the radio will be triggered. You will also need to trigger the button press for turning it on at least once.
348 and 759: You need to send a text message to activate the display; otherwise, it will simply remain stuck on the Opel logo. When you initiate sending on 348, the text will actually be sent to 759. In the message on 759, in addition to the text itself, there is also information about the message length (how many messages the text is divided into) and the character length. Some byte(s) are also used to specify the target location of the text.
3D0: Here, a specific message is sent regularly. Think of it as a kind of 'Keep-Alive'.

Even though I had a similar starting point: It's not easy for beginners. I spent weeks, or even months, sitting in my Vectra C (with a newer CID) almost every day for hours with my laptop, feeding the display with my own data. It's not something you can just whip up in two days, I'd say.

Hello shavenne,
Happy New Year!
Thank you very much for the detailed information.
"My question might sound a bit silly now, but what do you use to send and receive these messages? I don't want to put a PC in my car. Did you build the controller yourself, or is there something ready-made for that?"
Best regards, Flo.

I'm using an Arduino with an MCP2515 CAN controller and an MCP2562 CAN transceiver. There are also ready-made shields available for this (like the CANdiy Shield). That's how I started .

Hello everyone!

I also have a direct question about this topic:
I have several Arduinos and an MCP2515 CAN controller lying around. Now, I would like to read the steering wheel control commands in my Opel Astra H. In another post, I read that they are supposedly located on the Mid-Speed bus. Could someone please briefly explain to me how I can use the Arduino to "listen" to the bus? Do I have to program the timing, etc., myself? If so, has anyone already done something that I could build upon?

I am very grateful for any help!

Best regards and thank you very much in advance .

Find an MCP2515 library on Google.
Possibly, you may need to modify them because they often can't handle the 95.2 kbps bitrate.

Here are the corresponding values you need to add the bitrate:

Code:

#define MCP_16MHz_95kBPS_CFG1 (0x03) #define MCP_16MHz_95kBPS_CFG2 (0xBB) #define MCP_16MHz_95kBPS_CFG3 (0x07)

Most libraries also include examples. With these, you should be able to understand most of the functionality relatively quickly. The "most" refers to the fact that if you allow all data to pass unfiltered, you might miss some messages because the Arduino might not be able to process them quickly enough from the buffer.

You can receive the LFB messages on ID 206 (HEX).

Hey,

Thank you very much for the super quick response!
By the way, I just realized that I have a module with a TJA1050 transceiver, but hopefully that shouldn't be a problem.
I'm going to try it out directly in the next few days. Especially the tip about the 95.2 kbps is very helpful, thank you!

I have one more small question: Do I really need to connect to pins 3 and 11 in the OBD port for the mid-speed connection? I also read about a different pinout somewhere. Thank you very much .
"Edit: I also read that the China-made clones often have an 8 MHz quartz crystal instead of a 16 MHz one. Are there any libraries that support this, or do I need to replace it?"