I have a rather complicated project, but most of it has a solution.
I want to do a "Viper" type smart remote starter, but of course way cheaper and more customizable. It would have a remote start with an app on my phone, multiple Aux options(rolling windows down, heating the seats, etc), a GPS to track where my car is (just in case, or to make sure my gf is not trying to get away with it ).
On my way on the DIY route, I found no information about the "data-link" (call it iDatalink, DBI, D2D, RS-232, DEI) serial port and have no idea how it really works. I have this feeling it would be easier though.
Long story short, on the hardware side of thing, I would use a (DC) 12v to 5v converter to power the rpi, the 12v to 5v to 3v3 logic converter (yeah I know, tell me if you have any better solution, ebay doesn't seem to have any) and some relays.
Where I'm stuck is on the schematic of the bypass module / CAN interface. It has a couples of negative voltage going to and from the remote starter (the raspberry pi in this case). I have absolutely no idea how to use it. I searched a bit around the web but nothing to make me 100% understand what to do.
If you have any suggestions for anything that might be doing wrong, what ever it could be, I really appreciate it too!
The car for the project is a 2016 Subaru BRZ manual Sport Tech (push to start)
(Here's the schematic P.17)