How To Build Your Own Cat Door

[Dino] continues his to satisfy his weekly hacking goal by building a cat door for his pets. He has a Habitat For Humanity resale store nearby that was doing a 50% off sale on doors. So he picked up a six-panel door and set to work.

The first step is drawing out the opening and cutting it with a jigsaw. Once he was done, there’s some reinforcement work to be done because this is a hollow-core door. Since he had already cut a bit of the bottom off of the door to fit his jamb opening, he had some wood stock that was already the right thickness. That bit was secured to the top and bottom of the opening with glue and some brads. The same was done on the sides with a different piece of scrap, then the door was hung in the opening to reach the point in the project seen above.

Here [Dino] prepares to add a flap to cover the opening. He used acrylic for the flap because it’s light-weight and clear. A piece of piano hinge makes it easy to swing in both directions. The final touch is a magnet which keeps the flap from swinging in the breeze using parts from a magnetic cabinet latch. No sooner does he have the flap in place than a brave kitty gives it a test run.

Hopefully he doesn’t have the kind of pests that caused other hackers to build facial recognition cat door locks.


29 thoughts on “How To Build Your Own Cat Door

  1. Personally if a classic door with a window is salvageable at all, I’d repair it before, I’d replace it with a hollow core door that lacks a window.

    Because I have a rural residence a cat door isn’t an option for a lot of reasons. When I did have cats that where allowed indoors, when they where out they may have to remain out for quite some time. I have cats decide they wanted to be outdoor cats exclusively, and never wanted inside again.

  2. I have had an idea in mind for a cat/dog door that would only open after reading my cat’s microchip. My problem is that I am not sure exactly how the chip in my cat communicates. I am assuming it is RFID but the SPCA has no idea on any tech specs including who makes them (I guess they just look around for something “microchipy” and stuff it in your pet)

    Anyone know anything about them?

  3. Since its a hollow core door if you throw the cat at it hard enough you’ll have a cat door pretty damn quick! But really I don’t think a hollow core door is really secure for an outside door.

  4. I would be pretty worried about having a hollow core door as one of my exterior doors. The cat door is small enough as to be fine, but it takes very little force to go right through a hollow core door.

  5. Never thought to put a cat door up as a hack. I had built one two years ago. It was actually a tunnel of sorts that ran through the wall and 2 feet onto the patio. It had insulated walls and a roof. The roof extended out so the cat could sit under it during the rain. The tunnel had strips of material hanging down from the top that served as a wind barrier and it had the added effect of cleaning the cat off when he walked into the house.

  6. although i agree with the comments about the hollow core door, it is for a his backyard and I’m sure he lives in a rural area where break-ins aren’t really a thought. As a fore-thought though, Dino seems to know his way around carpentry and as with most carpenters that I know, they keep loaded weapons around the house. So as for any “would-be” burglars, they would be staring down the barrel of a loaded 12 gauge I’m sure. I’d be more worried of the insulation issues with the hollow core.

      1. Uh, quite the opposite.

        Are you one of those people that think you’re safe from a robbery attempt if you have no money in your pocket, but somehow MORE likely to be robbed if you have cash on you? Crooks can small money?

        What do you base your anti-gun statistics on? I know it isnt from FBI crime statistics.

  7. This is a TEMPORARY door until I can get a solid core door installed along with a dead bolt later this month. The original door couldn’t be cut be cut because I’m renting this house and the landlord wouldn’t approve. As far as other critters coming in, I’ve had cat doors in houses I’ve lived in for many years and I’ve never had a problem with unwanted animals entering through said door.

    1. In that it has been 30 years since I had to rent, that hindrance rarely enters my mind much anymore. In light of the landlord, not using the original door does make sense, but it’s still a shame having to replace a classic. While it’s relative, I have had racoons try to make their own entrance, and I have no doubt those black cats with a white stripe down their back would try to make use of such a door.

    2. Ignore the negative comments..I personally would love to make my own alternative cat flap…(diy or shop bought-still means cutting into the door..& judging from the ones available…don’t look very draft my door is thicker than I’m finding it difficult to find a suitable one that I can afford…(I actually thought a expell air vent if adaptable..what do u think..

    1. interesting comment…
      probably a chance that he is listed in the phone book under his name.

      And if not the phone book then a whois on his domain would probably take you to his door.

      Whilst I’m sure that nothing will happen, it’s an interesting look at just how “guarded” you should be when essentially giving away details of your home security in the name of trying to be helpful and post videos of other stuff.

  8. Letting your cat outside is being a bad pet owner. I dont need your cat roaming the neighborhood, do I get to let my pitbull roam free?

    Stop being BAD pet owners and leave your cat inside or if outside on a leash or on a tie out.

    1. 1) A cat can’t tear the face off a child the same way a pitbull can.

      2) A cat left on a tie has a good chance of hanging itself when it tries to jump a fence. That is not being a good pet owner.

      3) Keeping an animal like a cat inside is generally not good for it’s mental well being, as anyone who’s ever had a purely indoor cat bouncing off their walls will tell you. Again, not being a good pet owner.

      1. 1) But cats do dig out and poop in my veggies, but then again, I’m supposed you’re another cat owner who doesn’t care much about whether your critter is a nuisance to your neighbors.
        2) Hanging itself? You might just become a good neighbor.
        3) … and thus, people insisting having them as pets are egoistical and put their own pleasure before the happiness of the wild animals they keep hostage.

  9. Agreed, Kitty does not need to “roam free” they cause property damage, and it’s just plain bad manners to let your pets wander around onto other people’s property. Male cats will spray everything causing a stench that nobody likes and is impossible to eliminate, plus cat’s crap in childrens’ play areas, kill birds at bird feeders,etc… the housecat is one of the only animals that will kill for sport, I have had neighbor cats kill all the fish in my pond, leaving the dead bodies just next to the pond’s edge.

    Bad neighbors let their cats roam free.

  10. @meatman

    No it’s not. Cats are roaming animals and have huge territories. Letting them live in a small enclosed space all their lives is being a bad pet owner.

    Also although I know it doesn’t happen that often with dogs, cats never chew the face of a baby if they have a bad day. That’s why they are allowed to roam free.

    And they even help to keep the population of rodents and pigeons down a bit.

    I’m so sick of the butthurt dog owners that complain and try to parallel their cases to those of cat owners.

    1. Inb4 the shitstorm.

      I’ve been brought up with big dogs. And dogs are great animals but they need time and attention. Like a pack leader to take them out on treks every day.

      Cats are more individualistic and need to do things by themselves now and then.

      Also while sniped cats do still pee it does not smell much.

  11. Dino and his hack-a-week are great. You can bet he’s a responsible pet owner and a grey-hair who you can really learn a lot from. To me, he really embodies the hacker/builder ethos. Thanks Dino.

  12. We have some real cat/pet lovers here I see … I’ll take animals over people any day as companions, but they are not too great on tech talk. At least I can tell Dino certainly loves his pets.

    @Dino, you might consider two magnets rather than one and the metal plate for a bit more resistance. Adding a slide bolt for unauthorized entry times (night) might be a good idea too. Raccoons can be very destructive and/or very aggressive when cornered.

  13. I agree with SmokinCharlie (not with chipping an animal), it would be interesting seeing how to make the door unlock only for the right RFID code (placing the chip on the collar with metal under it would keep a significant amount of its transmitted radiation away from the cat). Any plans to make this let in only cats you specify?

    1. I just installed a couple commercial cat doors that had a magnetic “bell” included which was to be placed on the cat’s collar to “authorize” entry through the door. This solves the wild animal problem, and also will keep other pets from the neighborhood out which don’t have the same magnetic “bell” on their collar. As far as I could tell, there is no “chip” or electronics required at all. When the cat’s head butts up against the flap, the magnetic latch is “unlocked.” I’m not entirely certain how well it works, I did notice that feature could be disabled, and still have the latch stay closed and not flap in the breeze, as some flexible doors would. These had a two-part “hard” door, a clear and a white plastic part (the clear swings one way, the white, the other.)

  14. I’d like to put a cat door in an outside metal/screen door. My cat is mostly an indoor cat and when she does go out I trained her from a kitten using a leash to make sure she stayed in the yard. I guess it’s just a matter of cutting into the bottom section of the door and bolting on a flexible door like this guy did. Only thing is property value might go down and the next owner might not like the hole in the $200 metal/screen door. By the way, wouldn’t a nice framing job make the guy’s cat door look a lot better?

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