How to build a doorbell and cat-cam with Raspberry Pi

If you have a cat that likes to spend a lot of time outside, there’s the question of how you should let the cat enter and leave your house without putting your residential security at risk. 

One seemingly obvious answer might be installing a cat flap. However, as the Devoted to Cats website warns, you would need to teach your feline how to use this flap – and it could even pose a security risk in itself if, for example, it lets burglars poke their hands through. 

It would therefore be convenient for you to offer your cat a means of access that allows you to keep the door as secure as it always has been. This situation begins to explain the appeal of building a combined doorbell and cat-cam with a Raspberry Pi as the unit’s ‘brain’. 

Where you could take ins-purr-ation for your creation

One cat owner, Tennis Smith, has already used a Raspberry Pi to make a cat doorbell. It works in a wonderfully simple way: when the doorbell hears what it discerns is a meow, the owner is sent a text message.

The doorbell comprises a small box positioned at cat height and containing a small USB microphone wired to an RJ45 adapter. A CAT5 cable – what else? – connects the RJ45 socket to a Raspberry Pi situated inside the house. 

On the Pi itself, Amazon Web Services (AWS) software and the TensorFlow Lite machine learning app have been installed – enabling the device to not only pick up meows but also refer back to a database of meows so that only seemingly authentic ones are acted upon.  

Is there a claw – oops, we mean flaw – to this device? 

PC Gamer hardware writer Jorge Jimenez has commented: “I’m hoping the database contains some pre-recorded meows of Milo (Tennis’ cat), so it can tell the difference between him and some trouble-making sway.”

Otherwise, Jimenez points out, “every kitty in the neighbourhood could prank the doorbell day and night.” Theoretically, however, this dilemma could be rectified with the addition of a Raspberry Pi-compatible camera module to the doorbell setup. 

A range of camera modules of this description are available from online store The Pi Hut – and, if you are intent on making your own cat doorbell like the one described above, it could be beneficial for you to source one of these modules for it. 

That’s because the module could be added and connected to the doorbell in such a way that, from your smartphone, you would be able to see a live video feed of what is happening in front of the doorbell. 

That way, if the doorbell is triggered by a meow, you could simply look at the live video feed to see whether your cat is indeed waiting at the door. If you see a cat that isn’t yours, you could simply deny entry. 

Tennis has said that his cat doorbell project should be completable in an afternoon for someone who already has all of the required components at hand.