On 06/08/2019 18:53, ARW wrote:
Any recommendations for one?

Two cats and the owner wants no aliens in the house.


There was someone who used to spam newsgroups with such a product
sometime ago. So not a recommendation no matter what that is.

I'd go DIY, some sort of two-factor authentication.

i.e.
1. machine learning, so that what looks like a cat is identified as
being a cat,
2. having a microchip.

A laser to vaporise subjects that fail that would be a natural upgrade.

--
Adrian C