Making a cat scanner

Our cats are chipped with an Rfid tag. I want to read out those tags each time they walk through the cat door to get an idea about their nocturnal activity.

The plan is to use an rfid reader connected to an esp32. The esp32 will send data (the rfid id) to a hass webhook.
In hass I will do some kind of automation to pick up this webhook signal.

In the end I’d like to have hass to register ( in the database) each time a cat is scanned.
And I want a card in the UI displaying info like this:

Cat A: last seen: 16 hrs ago
Cat B: last seen: 1 hr ago

And at that last part I get kind of stuck and wonder whether you guys have any suggestions:

I don’t know if and/or what kind of component I should use to display these
“scanned events”. I guess it should be some kind of sensor, but can’t seem to find the correct one.

Any suggestion welcome!



One way to do it could be:

Binary sensors for each cat rfid detection.

Template sensors that report the last updated time of each binary sensor.

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I think this would be a good solution

It’s not the rfid part that’s a challenge. It’s the hass implementation

Thanks. I’ll try that

How about using ESPHome?
I see some RFID readers are supported, and ESPHome is well integrated with HA:

That’s strange! I looked at esphome but couldn’t find an rfid scanner. Gotta have my eyes checked!

Its not on the front page, but a search turned it up

Thanks! Now waiting for my esp32 to arrive…

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I don’t think the chip in a cat is on the same frequency as regular rfid chips. Worth a look at this video:

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You would likely need something like this and somehow figure out how to read the data.

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Have you seen this thread?

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I am aware of the sureflap devices etc. But it is much more fun making one myself :wink:


@stevenhorner Not 100%, but I am pretty sure the rf scanner works on my cat. I will let know my findings!

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@stevenhorner Unfortunately you were right. Most rfid scanners (like the rdm6300 I have) operate on a different frequency than the tag which is in my cat.

I have a tag which works with both the rdm6300 and the cat scanner. That’s why I made the (now false) assumption that it would work. But scanning my cat with the rdm6300 doesn’t do anything unfortunately.

So no cat scanner for me I’m afraid. !

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Ah that’s a shame :frowning:

For your information: I just tried to “scan” my cat on the Doorbird RFID scanner - without any success…
Lots of fun though :smiley:

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Helloo there, after a lot of research i finally heard of a person (you) that’s looking for something similar as me :joy:. I want to somehow make an rf detector that will alarm me (by noise- alarm and mobile notification) when my cat tries to pass through the entrance door. The purpose here is to improve safety for my cat, as i share the house with more people and i’d like to exclude the possibility of my cat escaping the door because someone did not pay the proper amount of attention. I went through your thread and that you tube video someone replied to you. Do you know how this idea of mine should be appliable? Myself, i don t know how to make an automated system like that but since i get some perspective here, i could easily find someone to make it for me!
Thanks a lot, in advance, for reading my strange request

Hey what happened with this? I just started adding ESPhome devices to my set up and want a cat tracker and presence detection. Apple AirTags are quite large for a cat who isn’t used to wearing a collar at all.