Question about Aqara Vibration Sensor

I have tried the same but the signal does not reach from the metal prison of the letterbox into the staircase, up to the first floor and through the wall of the flat... But if that is ensured, it should work. The question is where to put it. On the flap, on the door or just in the compartment when something falls on it. I would have liked to try it out but just. Another question is the logic. The alarm is also triggered when you take a quick look inside to see what's inside. I don't think a gust of wind is enough.

You can adjust the sensitivity in the Aqara app. So if it resonates too often, switch the sensitivity down a little (3 levels - high, medium, low).
As already mentioned, you need to test whether the signal reaches your letterbox. If not, you may have to move your Aqara hub close to the letterbox.