CAN bus sniffing

[Kayos]

Having installed an Android head unit in the Freelander, and sorted the correct decoder box with both high and low speed bus connections, I was a tad annoyed non of the exciting stuff shows

This is a software issue, and as I don't feel like writing an app, I am sniffing the high speed network with a can to usb adapter and some Linux command line fun

I've identified a couple of parameters so far, need to do some methodical logging and work out what is what

The plan is a small display showing things like what the Haldex is doing etc

More to follow

 

[dyno-tron]

I’m just about to start building a CANbus system for my race car, esp32/stm32 and Claude doing the clever stuff :-)

I’ll be watching this thread with interest!

 

[jmp49]

you can install torque on the android head unit and connect the usb adaptor to the head unit for datalogging and some codes.
Theres a android dash app that you can expose any pid from the canbus to via torque pro and build custom clusters right in the gui.

GitHub - agronick/aa-torque: Performance Monitor for cars with Android Auto

Performance Monitor for cars with Android Auto. Contribute to agronick/aa-torque development by creating an account on GitHub.

github.com

If you just want to mess round with canbus and a esp32 go for it though, I've been most of this week knocking up circuitry to make a boundary wire dog fence that works with the petsafe collars, but has a esp32 so it can report fence issues/status to homeassistant instead of just going deaf but ignoring it and not even lighting its fault led like the original unit does.

 

[Kayos]

you can install torque on the android head unit and connect the usb adaptor to the head unit for datalogging and some codes.
Theres a android dash app that you can expose any pid from the canbus to via torque pro and build custom clusters right in the gui.

GitHub - agronick/aa-torque: Performance Monitor for cars with Android Auto

Performance Monitor for cars with Android Auto. Contribute to agronick/aa-torque development by creating an account on GitHub.

github.com

If you just want to mess round with canbus and a esp32 go for it though, I've been most of this week knocking up circuitry to make a boundary wire dog fence that works with the petsafe collars, but has a esp32 so it can report fence issues/status to homeassistant instead of just going deaf but ignoring it and not even lighting its fault led like the original unit does.

Interesting

I have torque pro so no issue to get it on the head unit, guessing I still need to identify what I want to expose?

Being honest, I am enjoying the Linux stuff but if it can be on the head unit then it will be a neater install

 

[sako243]

Just waiting on some components to finish this off. Basically a digital gauge that chats to the 6x6 ECU I built but it's got the hardware on board to chat to CAN bus as I did that for a friend's digital dash I built for him.

Also full touch screen with swipe gestures working.

There's also provision for a GPS receiver on it so I could do logging of the ECU for tuning.

 

[jmp49]

Interesting

I have torque pro so no issue to get it on the head unit, guessing I still need to identify what I want to expose?

Being honest, I am enjoying the Linux stuff but if it can be on the head unit then it will be a neater install

Torque pro exposes a api locally that the other program uses, so torque pro is just acting as a gateway device.
You can add pids to torque direct also, https://wiki.torque-bhp.com/view/PIDs
If you add them I dont know if you can pop up a gauge cluster to track the custom pid you added and save the whole extra layer of the android dash app...

If you had a list of the pids around what you want to sniff for, you could use torque as the datalogger too

My lad runs torque on his generic android headunit with a wired usb adaptor plugged in that also goes to the cars original obd socket and he clears fault codes and datalogs stuff all the time and has a monitor for the temperature on his opel ashtray H since opel hide the actual temperature from the driver as it runs at 115c normally. Since most of the aftermarket android head units come factory jailbroken there's no google bootloader nonsense locking them down to certain app stores and sideloading to bypass.

I think if you look round the net, you'll find a set of custom pids for your car from the torque community already if its not very modded. This any help? If not because its too new its probably useful just as a walkthrough on how to do it in torque if nothing more.

 

[Kayos]

Some progress made today

Positively identified:
Neutral/First/Reverse
HDC request
HDC active
HDC incorrect gear
DSC deactivated

Close but not fully confirmed is Terrain Response mode

Once I have all that 100% I will start hunting the stuff that does not show on the display

 

[Kayos]

A 60 second log of all traffic is around 4mb, not huge but to get the above I have 10 log files.

Next step is to filter timing and handshake signals, I will also switch to Wireshark when I have more info on what I need, with human readable terms and clever filtering

 

[jmp49]

There's a set of filters for CAN for wireshark already:

Wireshark • Go Deep | Display Filter Reference: Controller Area Network

Wireshark: The world's most popular network protocol analyzer

www.wireshark.org

 

[Kayos]

Couple of screen shots showing the script I wrote for the bits identified so far

 

[jmp49]

Nice, you can add a custom pid for eg 167 now in torque if you want.

So something like this

Name: Low Gear Status
Mode and PID: 0167
Long name: Gear Position
Minimum: 0
Maximum: 1
Scale factor: x1
Unit: state
Equation: A
OBD Header: 167

The first bit in that thats important is the ID from your frame dump above which is listening to 0x167 (assuming your dump is in hex...) , then you map to the part of the message that indicates just clutch status which Ive stuck as A meaning the first byte of the message (this is wrong on reflection but you get the idea). You'll have to go through the pid outputs and check which byte changes between each state to map it in properly and write a equation that makes sense with the state changes. That example is for just a 0/1 binary state which probably in this case doesnt apply...
Once you have the custom PID mapped, you can just add a led indicator to the display if its a boolean, or digital display if you want to see transition values if the clutch sensor is capable of it and its exposed in the PID on canbus.