How to register if current is there or not

Projects Programming
1

Hi all,

I need my Arduino Uno R3 to register if there is current (12V) on two cables or not.
Perhaps it souds a little bit silly but just can't find a better description for my usecase :slight_smile:

So i have two cables on my car on which there is 12V when the car is running. I would like to use this in order for my Arduino to register if the car is running or not.

What is the easiest way to register if the 12V is available or not?

I was thinking to connect a relais to these two cables so it switches on when the current is there and then to use the Arduino on the other Side of the Relais to register the close circuit.
Is there probably a way to do this with a MOSFET or a even more simple way only with the arduino, probably with a analog input or so?

Regards and thanks,
Markus

2

What is the easiest way to register if the 12V is available or not?

Connect one end of a voltage divider (just a suitable pair of resistors in series) to the 12V source. Connect the other end to ground. Connect the middle point to a digital pin. If the pin reads HIGH, there is 12V. If it reads LOW, there is no voltage.