cat-localizer VS homebox

This is the way I would do it. You can even track where in the house the item is.

They are ESP32 with builtin power supply, I use them for almost everything. Temperature sensors (with the addon!), heater control, cat locator and, yes, for power monitoring. I set `PowerOnState` to `4` in Tasmota. Relays usually fail because of switching cycles, being always on is much less taxing.

I agree that gutting a chip reading door and using the mechanism to hold down the curtain of your door might be a viable solution, but to answer the actual question: https://github.com/filipsPL/cat-localizer

Look into cat-localizer, it uses BLE beacons.

The first time I read the post I also assumed the phones are the beacons and was about to suggest the cat-localizer, but actually OP is asking for the phones doing the tracking.

finally, a way to locate my cat in my house

As a self hoster and hobelabber I get a lot of things as stuff. I stumbled over https://github.com/hay-kot/homebox and it seems very interessting where you can also print qr codes. Any other and better options out there?

HomeBox might work for what you're looking for.

I self host homebox (https://github.com/hay-kot/homebox). It fits my purpose for tracking assets and includes enough features like purchase price, warranty details, QR code generator, and many more fields. I'm quite happy with it so far. It should meet your needs too

Check out homebox. It already supports some of these features, plus the dev is very active and responsive to feature requests, and uses it for their own personal maintenance tracking so wants to make it work well!

It is not meant for this, but maybe it works anyway? https://github.com/hay-kot/homebox

If that’s too much (and it is!) you can try homeboxmuch lighter for an household!

No I haven’t … and after a wild goose chase of trying to find what I think you were referring to as a few things seem to share that name , I found it so adding a link for others to see.. https://github.com/hay-kot/homebox