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How do microchip cat flaps work?

A grey cat about to pop his head through a microchip cat flap
(Image credit: Pixabay)

If you've ever asked, “how do microchip cat flaps work”, then chances are your home has been attracting some neighborhood moggies. Normal cat flaps allow felines to come and go as they please but the best microchip cat flaps place a restriction on who can enter. 

These cat flaps make use of the rice-sized microchips that many of us implant under the skin of our feline friends, typically between the shoulder blades. Each microchip acts as an identification device that contains a unique number. They allow lost cats to be scanned and reunited with their owners.

Microchip cat flaps contain a sensor. This acts in the same way as microchip scanners, reading the chip using Radio Frequency Identification (RFID) technology whenever your cat tries to access the flap. Doing so will obtain the chip's unique identifying number and this can then be checked against the one the device has stored. 

So long as there is a match, the flap will unlock and allow access. If the cat flap doesn't recognize the identifying number or if it doesn't detect a chip, it will remain locked. It's a simple concept and yet it provides great peace of mind while also ensuring that your cats retain their freedom. What's more, the cat flaps fit into doors, windows and walls, just as normal ones do.

How do you set up a microchip cat flap?

One of the first things you need to do is find out if your feline's microchip is compatible with the microchip cat flap you're looking to buy. Manufacturers generally list this so take a look at their website or study the box.

Next, you'll need to pop some batteries into the microchip cat flap. As you may have guessed, the technology needed to scan your cat's microchip requires technology but the good news is that these devices don't need to be hardwired.

When you're ready to program the cat flap, you'll need to make sure your feline friend is close by. You will then be required to set the manual lock so that your moggy can go in and out of the flap unhindered before putting the device into its learn or memory mode. This is usually done by pressing a button.

By then placing your cat's head through the cat flap (or encouraging your feline friend to do it themselves), the device will scan and save your pet's identifying number. Just don't allow any stranger cats to pop through before your pet otherwise it would remember their number instead! 

From this point, the door will close and the device will be in what's usually called the “primary” mode. The flap will only open if your cat tries to pop its head through. It will remain shut for other cats and animals. What's more, it will only open if your cat is actively trying to get in. Approved pets can't just wander by and unlock the flap, allowing any other passing animals to take advantage.

Do microchip cat flaps work both ways?

Some microchip cat flaps work both ways but some don't. Simpler microchip cat flaps will be selective about which cats are able to enter your home but they will let any moggy out without checks. This can be desirable, especially if an unwanted animal tailgates your pet and manages to get in because it means they can easily get back out again.

If you have other pets, however, and you're worried they might take advantage of the cat flap and decide to pop outside, you should buy a device that scans both ways. 

In any case, you will be able to lock most cat flaps in one of four positions depending on what you're looking to achieve. These include allowing entry and exit or completely locking the device as well as two other useful functions.

You could, for example, allow a cat to enter but not exit which is ideal if you're hoping to take a cat to the vet within the next hour or so or if you'd like to keep the moggy in overnight. You could also allow a cat to leave but not come back inside your home for a short while. This works well if you have a visitor who is allergic to cats or if a friend has brought a dog who may not rub along well with your feline friend.

A ginger cat tentatively peering through a microchip cat flap

(Image credit: Pixabay)

What is a dual scan cat flap?

But what if you have more than one cat? Well, most cat flaps will allow you to store a large number of unique identifiers – anywhere between 25 and 40 in some cases which is plenty for most of us! But if you do have more than one cat, then it's worth investing in a dual scan cat flap – or DualScan as it is written.

These cat flaps give you an amazing amount of control because it's a technology that not only scans when a cat is exiting as well as entering a property, it also allows you to program the device for individual felines.

Let's say you may want to take one of two cats to the vets. In this case you'd prevent one of them from making a run for it through the cat flap but you'd allow the other feline to come and go at will. Usually, with this technology, a cat that does manage to escape (through an open door perhaps) will be allowed back in again. It's the ultimate technology for multi-cat households.

Should I buy a microchip cat flap?

Certainly, microchip cat flaps are better than basic ones. Although a non-powered flap will allow you a modicum of control in the shape of a little piece of plastic that you can use to open and close the device, microchip cat flaps prevent intruders. 

You could team them up with one of the best pet cameras to keep a closer eye on your feline's coming and goings. In short, they help your cats to feel safe in their own home and ensure no other animals are stealing their food. Installing and programming them is also quick and easy. The only downside is they are a little more expensive but they are totally worth the cost

David Crookes has been a journalist for more than 20 years and he has written for a host of magazines, newspapers, websites and books including World of Animals, BBC Earth, Dogs and Canines, Gadget and The Independent. Born in England, he lives in a household with two cats but he’s also keenly interested in the differences between the huge number of dog breeds — in fact, you can read many of his breed guides here on PetsRadar. With a lifelong passion for technology, too, he’s always on the lookout for useful devices that will allow people to spend more time with their pets.