I would like to be notified when I receive mail through a slot with a hinged flap, that is mounted through the garage wall. The Ooma motion detector works sometimes, but it is not reliable.
I tried shorting the contacts of a water sensor but that did not work. Either it will not respond to a short circuit, or it only reports after a set time, i.e., to avoid false alarms.
It would be impractical to mount a window / door sensor on the flap or the wall.
Does anyone have a suggestion or a thought to share?