I'm using Pi 3
I have a line that gives 12V. I need to invoke something on Pi, when the line goes High.
As I cannot connect the 12V to GPIO, I thought of using a relay, that will trigger on 12V, and then connect the 3v3 to a GPIO.
This will happen periodically, for almost a second.
I know that the 3v3 will have current that is unused by the Pi, but in this case I cannot always be sure how much thag would be.
Is this safe?