Well, yes, i bought a 6 volt regulator. in the car's fuse box, there's a fuse for the alternator reg, that's only hot when the alternators outputting a charge, i've disconnected the fuel pump and attempted to start the car to check this.
i was going to put the 12v regulator in between that, and the arduino input pin. is 6v safe for the arduino "in" pins to handle?
And the code for that would also protect from firing the startor motor again such as giving it a way of checking before doing anything that the car's not running.
"am i getting an input from alternator?, yes i am, so don't allow the following code to be run"