I'm building a box that will turn on my car's engine block heater during the night.
The arduino circuit will "talk" to my controller inside the house via RF24.
It's all sorted, except now that I'm looking at some details about boxing it, I realised that the voltage regulators 7805 are not rated for operating temperatures below 0C.
The whole point of this box is to be left out when it's -15C, -20C, -30C.
What would you suggest?