I've been looking around for an easy way to convert car battery 12v to 5v. I have seen some people saying that a simple resistor is all that is needed.
What I've tried so far is the DC to DC regulator. It works, but it's pretty expensive for such a cheap project. And not to mention it is twice the size of the project.
Following the ohm's law, it should mean that a single resistor with appropriate wattage rating should be fine to convert the car battery into a 5v supply. But the project used a max of 350mA, will the resistor or the project burn?
EDIT: The project will run even with ~100mA supply, but at some points it could go way up to ~350mA. Haven't tested it thoroughly but atleast 500mA would be sufficient. And yes, since it's a Microcontroller, a stable 5VDC would be preferred. And about destroying the OBD2 ports... Really I never had any thoughts about it.