AVR Guardian Filters Out Dogs

Cats and dogs can get along quite nicely when they are raised up together. The problem with this type of arrangement tends to be keeping dogs out of the cat box and away from the cat food. [Ryan Meuth] tried out a simple electronic barrier to keep the dog away. It uses an IR transmitter and receiver to shine a beam of invisible light across the doorway to his cat room. In the demo after the break you’ll see that he took steps to make sure the cats don’t set off the alarm. The beam of light is set high enough that their bodies don’t get in the way, and the firmware measures the amount of time the beam was broken in order to avoid false positives caused by the cats’ tails. If the dog does try to get into the room it will break the beam and set off a high-pitched alarm sound.

It’s interesting that the dog doesn’t like the sound but the cat’s don’t seem to be scared of it. Also, we’ve got a less-than-ferocious feline that would love to chew on the cord that connects the two modules. Still, it’s a solution that works for [Ryan] and could be incorporated into an automatic feeder to keep the dog away from feedings while you’re out of the house.


29 thoughts on “AVR Guardian Filters Out Dogs

  1. It reminds me of a chastity belt, because it protects a … anyway, its a clever design, if you can hide the cord, but what if the dog figures out jumping over or crawling under it?

  2. I’ve always wanted to get my animals chipped (RFID chip embedded in their neck for if they get lost. this is common and i should do that anyway) and then build a reader that can tell which animal is which, for this kind of thing.

    I have a couple kittens and an older cat. They always eat eachothers food and then puke it up on my floor. I’d like to build a box that only let the right ones in it to eat.

  3. are uControllers making people forget about electronics?

    This is a fairly simple problem, which could have easily been accomplished with a few transistors and a 555.

    Not that this is a bad thing, it opens up a lot of potential for expansion, but it just seems overkill at the moment.

    I really hope electronics as I know it doesent die off as a result of uC’s.

    I do love them, but when they are used to their potential.

  4. great idea. i would use two receivers so i could tell which way the obstructing object was traveling. kinda how a two channel incremental sensor works. why would i want this? what if fido somehow ninjas his way past the alarm system then can’t get back out? if the owner is away for too long, fido would have to live off of cat food. if the owner was away for the weekend, fido would have to eat the cat poop. and, if the owner went on vacation, fido would have to survive on a diet of cats! oh the humanity!

  5. Here is a lower tech solution that I recommend and use to keep my dog out of the bathroom with the kitty litter:

    It is a “hook and screw”, “window hook”, or “safety gate hook” that is long enough to let the cat through but not the dog.

    Make sure that either the hook is high enough that the dog cannot reach it or opt for the safety version.

  6. Wow, that’s an awesome pet hack. I’m not smart enough to figure something like that out.

    We would just have to use our Havahart Wireless fence indoors if we ever got a cat, but I’m not planning on that happening any time soon.

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