Im looking to built a canbus filter inline, to remove certain data from point A to point B.
I would love advice on what to buy to get the project started, if i need anything.
I have already decoded the canbus data and addresses, i just need a way to allow everything but certain data. Automotive project.
Could You draw a principal diagram to make it clear?
What controllers and other devices do You intend to use?
The Arduino Due plus 2 genuine (non-fake) transceivers is one option.
Avoid Ebay, Aliexpress and Amazon as most stuff is fake.
Really in the infant stage, its been a while since ive messed with arduino.
Im basically trying to stop certain data coming from bosch ecu, to go to another module.
Ficticious Example, if vehicle goes over 100mph the wing angles down. The ecu feeds the data to the module, so if i could stop the info, or modify it to show lower value, it would be great.
Im not familiar but i will check out the Due
I dont see the due plus 2 listed anywhere, possibly discontinued?
That sounds dangerous. Mistakes in coding might make the car unstable, unreliable. Surely the designers knew what they were doing.
0 danger in my application. Nothing critical controlled via can, only engine, which i already control and program. Not a vehicle used in public, and not driven. Only used in static, controlled environment.
Okey.
Check up what speed the CAN bus i using and look for CAN interfaces matching it.
The built in examples, in the IDE, might provide code material to start from.
I believe its 500k, i have pulled canbus stream before on an old board with can shield.
Good.
Then catch the messages and try picking certain messages.
But im unsure how to play the middle man between the two existing modules communicating.
Would i need two arduinos? One to receive info coming from ecu...remove or alter the message...then output from the 2nd?
If i knew what to buy, i could get everything and when i get stuck...ask more intelligent questions.
That would complicate the project by a factor 4 and make it slower.
As already said, start by identifying the target message.
If it is the target, manipulate it and send it. It not the target message, send it.
I don’t think you can do it as the modules respond to data they consider theirs . You can’t “ block traffic “ on the Can Bus from reaching a particular module .
You need to create a gateway and catch the signals as they come from the source and discard the unwanted but pass on all of the rest. This module will have two can busses and pass all downstream to the upstream module. Be careful of some of the signals are time sensitive. If something is looking for this signal it may fault out on you.
So a CANFduino would be a good option? It looks like that will be what i need to possibly simplify things.
I am not familiar with it but a quick check says it should work and do what you want. Be sure you have another CAN device on the bus while doing initial checkout.
What do you mean?
So what i imagine is having this between ecu that is transmitting and the module that is receiving.
Interesting, how will you accomplish that without a major rewire. Pass all the signals through it. Filter out the ones you do not want and pass the others. Be careful of latency, the ECU (Engine Control Unit) has some critical timing signals. Messing these up could damage your engine. Read the following if this is going in a real vehicle. The code is going to be the easiest part. Check this to get an idea of what is there:
There is many good app notes such as AN2689 by ST on automotive electronics. reading it will help you a lot.
https://www.st.com/resource/en/application_note/cd00181783-protection-of-automotive-electronics-from-electrical-hazards-guidelines-for-design-and-component-selection-stmicroelectronics.pdf
Also take a look at these: https://www.analog.com/en/technical-articles/distilled-automotive-electronics-design.html and
Transient Voltage Suppression in Automotive Applications
AEC-100 https://media.monolithicpower.com/mps_cms_document/w/e/Webinar_-_Fundamentals_of_AEC-
On paper it is not hard, in hardware it is very difficult.
The engine will get its info directly from sensors and will not be impacted by canbus data. The ecu will send out that data (example...like sending rpm value, or fuel level to cluster). Now if you alter something like throttle value...yes you could potentially hurt something...but in this case, not really. It will only be run on bench.