For my snail mail notifier, I'll use three switches (reedswitches or contactors):
- One on the flip cover in case I receive a letter
- One on the front door in ase I receive an unregistered package
- One on the back door to know when the mail has been collected
When Arduino detects mail arrives or is being collected, it will send a 433 MHz signal to a Raspberry Pi that wil do its magic (send me an e-mail and display something on a TFT screen) one or twice a day. Hnce, it wil sleep the vast majority of the day.
In your opinion, what will be te best way to wake it up when a door or filp cover is opened?