I'm about to purchase a new vehicle (a 95 LR Defender 90) and want to 'make my mark' on the electrical side of the car.
I'm wanting to create a custom switch panel to control the various lights in and around the car which is going to use an arduino (board depending on number of input/outputs, of which hasn't been decided yet).
I'm thinking most outputs, obviously via a relay, will require 2 inputs, one to toggle on or off, the other as a momentary operation (switches will probably be momentary MX cherry keyboard switches as I can get custom designs along with backlighting). So far should be relatively straight forward?
I think my bigger problem is that I'm also wanting a secondary switch panel in the rear of the vehicle, hardwired to the main switch unit rather than wireless.
I wont necessarily need all of the options repeated on the second panel, but Im unsure of the best way to connect them without individual wires. Would individual cables be best, meaning maybe a 10-core cable, or would a second Arduino and I2C be a better option?
I've never dealt with multiple boards working together before so any help would/guidance on the best approach be appreciated.