I have a chinese arduino nano that I'm planning to use to open a door using a numeric keypad.
My power source is 12V and I want it running 24/7. I have read that the first thing to fail on an arduino is the voltage regulator due to the heat of lowering the voltage to something the arduino can use.
I have think of buying two big resistors of around 1W each to build a voltage divider and only feed 7V to the Vin pin of the arduino, so it will increase its lifespan.
Is this a good idea?