dennis@home wrote
Rod Speed wrote

And just typing that makes me think I should put one in the
letterbox so I get told when it gets opened, and it shouldnt
be too hard to ensure that it can't get pinched easily by having
a plate screwed in over it. Not sure if it will work tho since the
letterbox is all metal so the wifi can't easily get out. Maybe
I just need a plastic box under the letterbox with a hole in
the bottom of the letterbox that the sensor looks thru.

Cheap ultrasonic distance sensor so you know how big the package is?

Dont care how big it is, I want to get it before someone
helps themselves to it, even if its just a letter, So just
need to know when the lid is opened, even if its just
some arsehole checking if there is anything in it etc.

Put a magnet on the flap and a reed switch to detect it opening and an
esp8266 to send the data?

The problem with the esp8266 over a Hue motion
sensor is powering it and having it fully integrated
with the homekit system that all the other hue
motion sensors currently use. That something
another hue motion sensor would do trivially
and they do the battery power themselves too.

While they are stupidly priced, all I need to do
is something very basic to stop any arsehole
from taking it away and to allow the wifi to
work. They are zigbee so range isnt a problem,
they talk to any other in the system.