Has anyone used these or other to trigger external outputs when certain CAN data is met? An example would be a warning light on the dash if fuel pressure drops too low, etc. Ideally it would be something that you could program and hardwire to the vehicle so that it runs automatically when you start the engine, and shuts down with key off. I see they offer add-on modules for CAN communications, but I am not familar with using them, or what hardware would work best for this application.
I am no expert but getting an Arduino or rasberry pi to listen and talk to your CAN buss is easy compared to the real trick of then to reverse engineer the communications so you can know what you are hearing and what you might want to say on the network. Its like reading a page of HEX and trying to figure out what is being said about fuel pressure.
You can use either Arduino or R-PI with a serial interface. All CAN buss is serial communications and follows the official CAN protocol. Since CAN was originally a Texas Instruments product, you can search the internet for a HMI program to decipher the CAN traffic and with effort, figure out what you are seeing. There is some useful contents in the CAN protocol to give setpoints and input tags. Wireshark(free) will show the data but like OBThomas, it is ugly unless you know what you are specifically wanting. Here are 2 links for some software (I have not tried it but have used many other industrial vendor serial protocol software platforms): https://rbei-etas.github.io/busmaster and https://netcult.ch/elmue/HUD%20ECU%20Hacker. Here is a link for CAN standard information https://www.analog.com/media/en/tech...es/AN-1123.pdf. I am a retired industrial control system cyber security expert and I am very familiar with many of the 250+ industrial protocols. If you are new to industrial protocols, CAN or other serial (ModBus, BacNet, etc.) are a challenge to decipher because the serial traffic doesn't have any reference information (Example 12 of something and you don't know if that is 12 counts out of 100, 1000, or 10 (alarm or too high) so it will take some work to understand. Good luck and I will attempt to assist with guidance as asked.
Dakota digital has a cluster that is CAN enabled and you can add things like pressure and temp sensors for oil, trans, fuel, etc.