BestPractise: letterbox sensors

[Cplant]

I finally came across documenting my solution, which works pretty reliably now for two years or so. Feel free to have a look and comment:

Use case: Letterbox automation

My mailbox is ~5 meters away from my flat, so I thought it’d be fun to install hardware into the mailbox that a) automatically detects when a letter has been thrown in, b) detects when the mailbox is being emptied and c) notifies me via push notification, Alexa and an LED signal in my flat when the mailbox is full. Hardware / Sensors: My outdoor mailbox is a rather challenging enviroment (-10°C - +40°C, up to 90% humidity plus actual moisture in the mailbox during heavy rain). My first attemp…