Selecting a Single/Two-Wire Serial bus

Evening all (Or morning/afternoon, depending on the time of day you read this)

I'm working on a project for my vehicle which among other low-level functions is to control RGB lighting with modules in the doors, rather than running one big driver as I wanted a little more flexibility in the design. However I realise that there is a lot of potential electrical interference when running a bus wire the length of a vehicle among the possibility of high voltage spikes.

The main points is that there would be 5 main modules of varying capability:

  • Body Controller - Handles RF for a "Keyfob" for adjusting settings, playing audio samples through the radio/amplifier
  • Drivers Door - Handles 2 channel RGB LEDs, Mirror folding upon lock/unfold on unlock, Global Window open (for the remote fob to close the windows with one button) and general door open/lock status. Will not control locks
  • Passenger and Rear doors - Essentially just 2 channel RGB LEDs and door open/lock status

I looked into the current vehicle communication methods to see what existing options there were and found at least three options:

  • CAN Bus: Readily available, well documented but expensive to add and without running a third CAN it's possible to interfere with either entertainment or worse the engine data (huge no in my eyes)
  • K-Line: Already exists in vehicle is not used but from what I read and assume is primarily a diagnostics bus only and not supposed to be for general use. Plus carries the slight possibility of falsely triggering the diagnostics on the various modules. Also the libraries I've seen are used for diagnostics only, which again makes sense.
  • LIN: Seems to be the best option, albeit the small expense of running an extra wire but it's predominantly Master/Slave architecture which would work although I would preferably like the Drivers Door to send messages to other devices as well without the body module. Also the libraries I have seen aren't always general purpose and assume a master role, which usually makes sense but not in what I need.

Aside from that, it's making either my own or a derivative of the above that would meet the requirements. But before any of that, I was wondering if the forum had any experiences or any suggestions that could be shared. I'm of the opinion of using LIN albeit with the body and drivers door modules being "master" and the remaining being slaves but not sure how to arbitrate in that case, unless I could use a CSMA/NDA for it. That or to use a high voltage Serial line using RS232 communications (and not voltages) protocol and use my own design, but just worried about interference.

So yeah, any thoughts or ideas would be appreciated!

For a car I would always choose CAN.