How to check the presence of a thing in its place?

Question

Smart House

I am now playing "Smart Home" based on the system from Homematic ( article on Habré ).
I want to implement a security and burglary warning system. There are, of course, a bunch of different possibilities and scenarios, but all of them are insufficient from my point of view. Or rather, they are insufficient, taking into account the constant presence of a cat in the house :) In this regard, the use of motion sensors is no longer necessary, and without them it is difficult to implement a full-fledged system.
So the following thought came to mind. Buy a dummy Iphone, which costs a penny and looks like the original as two drops of water, and track its presence in a certain place. It is not difficult to assume that a thief, having made his way into the house, will not disdain such a little thing. Accordingly, as soon as the model disappears from its place, this can be considered a signal.
The problem is, I can't find anything suitable to track the movement of the phone. Maybe use not a sensor for the presence of things in place, but somehow use the phone's charging wire. This, of course, is also an imitation, but you can connect a dummy phone to one end of the wire and put some kind of sensor on the other end of the wire that can track, I don’t know what, maybe the contacts are closed on the other side of the wire.
In general, the idea is there, but there is not enough knowledge to implement it. And I don't want to reinvent the wheel. Maybe someone can suggest something?

Answer 1

Option 1 is dry contacts and any universal sensor.
Option 2: Take a door / window opening sensor. Place the magnet in the model of the phone, and hide the sensor itself under the table / shelf on which it stands. If the magnet is removed, the contacts will close.
Why are you not satisfied with the sensors on the door? If the door is not opened by you, then someone broke into the house?
Also, motion sensors can be configured to ignore pets if I'm not mistaken ..

Answer 2

Can't your cat throw off your dummy? I would place a simple bluetooth-wifi module in a dummy and monitor whether there is a device on the network. To protect against battery discharge - periodically helmet on bluetooth / wifi its status.

Answer 3

There is a new system natively supporting Homematic. See ccu.io/en. Its description can be found here:
www.ab-log.ru/forum/viewtopic.php?f=1&t=744
Soon there will be an article on Habré

Answer 4

I think it's easier to take and put a motion sensor in front of the phone. Now their sensitivity can be adjusted. Kind of like the Ajax alarm system . it also seems to me that it’s just easier to put a small camera, it can be puttied, for example, just to have a lens. And watch who is a thief and who is not a thief. + so that the alarm system is connected to the security console.