Blender Defender

Have a cat that won’t stay off your counters? I do. I finally got fed up with it enough to do something about it: scare the crap out of him with a motion-detecting blender (while recording the results for my own amusement, of course).

Confused at what you’re looking at? This is a repeating shot of security camera footage of my cat jumping on the counter – in search of a plant to munch on – and initiating my Blender Defender. Take a look at the following comic to get a better understanding 🙂



Sorry, but you’re going to have to pretend you can hear an extremely loud blender while you watch these clips



largedsc_4622If you were to walk in my house, you may see something you dont normally see in a kitchen. On the wall, to the left of my sink is a webcam (network camera). It is plugged into the network jack and screwed into the wall plate cover, supporting itself. It doesnt get it the way, nor do we ever have to think about it. The camera is being monitored for motion by my computer upstairs in our office.

The camera itself is one of the cheapest network cameras out there, the DCS-900. It can be picked up for about $120 or so. There are a couple network cameras that are a little cheaper, but the D-Link one is pretty rugged and makes it easy to get into the raw feeds, something that cant be said for many other cameras.

largedsc_4605As you can see from the videos above, the blender and the strobe light are both controlled by an X10 unit. The unit is sent an on or off command from the computer running upstairs by means of an X10 Firecracker. The Firecracker is just a wireless X10 transmitter that plugs into your serial port. I wont get into explaining it much here, but one thing to note is that is happily co-exists with my CM11A unit.

The computer upstairs is running the ‘motion‘ library for linux. As soon as it detects something moving on camera, it starts recording frames. While it is saving frames, it also initiates another Perl script I wrote that sends an X10 command to turn on the blender and strobe, wait 3 seconds, then turn them off. After the script is done detecting motion, it then splices all the JPG frames together using ffmpeg and saves the resulting movie as a SWF file, which you can see above. Finally, after it saves the movie, I have it set up to email me a link to the movie so I can see the results from where ever I’m at (remotely by using my phone).


Is this cruel?

lgcodygrassOf course not! To teach a cat not to do something, it has to get the idea that what it is doing is a bad thing. One way to do so is to sternly tell your cat ‘NO’ when it does something. The cat may learn that it is bad, but more often than not, the cat learns that it’s not supposed to it when your around. This is not what you want. The best way to teach the cat not to get on a counter is to take yourself out of the picture. If the cat jumps up on the counter and is greeted with a scare, it will learn that the counter is not a very nice place to be. The cat is never harmed, but it’s instincts tell is that this may be something to be feared. Just like a vaccuum. The cat doesn’t like it at all, so it stays away.

Some will say that the cat is trying to eat the plant because he needs it for his digestion. In this case, it’s just not true. Our cat doesn’t simply eat our plants. He sees them as a toy. He plays with the stalks, digs them out, etc. We find leaves in the other rooms half the time. And, yes, he does get grass every once in a while.

Project Cost

The table below shows how much money would normally go into a project like this. This isn’t to say that I’ve spent this much, as I already had everything lying around the place, but if somebody else were to start this project, this may be what they should expect to pay.

Item Notes Price
Strobe Light Bought from Spencer’s 20.00
Blender Housewarming present, woot. 50.00
X10 Firecracker Check Ebay and Amazon if you’re looking for one 12.00
X10 Appliance Module You wouldnt want a Lamp Module for this. 12.00
Network Camera D-Link DSC-900 120.00




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875 thoughts on “Blender Defender

  1. Given that the most recent movie is dated October 15th, 2008, and one of the earlier ones is dated July 22nd, 2008, I think we can conclude that the cat is '… persistent and stubborn like every other cat on the planet'.

  2. I'd like to see that hooked up to the fridge, so every time Brian opens it to stare he would get the surprise!!!! HEE HEE HEE

  3. Hey! I saw your project today on the Make Blog. Aside from it being utterly friggin' hilarious, it would be perfect for the contest we are having right now at Instructables. If you are interested, the details can be seen here:

    Otherwise, I must say again, as someone that lives with 5 cats (that aren't mine), this project is awesome.

  4. 2 things: #1 you have too much time on your hands. and #2, you have a terrible grasp of the English language. as an example: "Confused at what your looking at?". YOUR?? don't you mean "you're", as in "you are". this is something learned in 2nd or 3rd grade i believe.

  5. hey, nice blender.

    Listen, what do you do when you need to use the blender? I mean there seems to always be a somehting or other inside the blender…do you have another blender with which you can do everyday blender stuff?……

    what if you need to be in the counter… and then all this stuff is going off… man

  6. [b]@danny[/b]: I just turn off the script controlling the motion detection. We usually only turn it on at night anyways – he knows better than to get up there when we're awake 🙂

  7. Awesome project. I Love it. but how many plants could you buy for $214? there are plants that are sold just for cats to eat them, much cheaper. But still Awesome project. good job!

  8. I make slot machines so I know a thing or two about behaviorism and conditioning. I warn you that you're creating an unhealthy relationship between your cat and your blender. Don't be surprised if you find a cat poop smoothie.

  9. Just think: if someone ever tries to break into your house through that window in the kitchen, you'll get a video of someone having a heart attack on your kitchen counter… and then beating the crap out of the blender, camera and motion sensor…

  10. @johnb It's pretty hilarious that someone like you would go to great lengths to deride the author's grammatical mistakes when, judging by your own writing, one could only assume that your uncertainty regarding which grade the difference between "your" and "you're" is taught is simply because you never made it that far. And also, ur gay.

  11. JohnB, So your complete lack of proper capitalization, improper use of punctuation and failure to find the humor in this project make you some sort of English maven? Fail much? Seriously, go express your tarditude elsewhere.

  12. I agree. This is pretty sweet.

    @ John William. I agree with your statement all the way up until your last line in which you say "ur gay." I find the use of this term as a derogatory means as completely unjustifiable and ignorant. Please don't use gay in a derogatory manner, it is inappropriate.

  13. @John Williams: The last part of your comment where you said "ur gay" was the best part of it. I didn't really care for everything else you said, but I loved that last bit!

  14. @ Mom all you have to do to keep Brian out of the fridge is change the door handles to the other side of the fridge and the door won't open. Problem solved. Also its worth alot of laughs when to watch other people try to open the fridge.

  15. HAHAHAHAHAHAHAHAHA!!!!!! I love how that cat gets the crap scared out of it. You should make a kit with instructions and sell it

  16. This was obviously photoshopped, what a loser. John Williams I will beat "your" straight ass into the 9th grade if I ever see your ass in Glupo, Milwaukee. Degrogadory flute kisser.

  17. If you'd just kill the cat, you could have saved yourself $214!! How about making something that impales the cat on the end of a spear or other pointy device?!?!

  18. Yeah great, the cat probably just wanted to go to the toilet in the sink.

    So he is effectively training the cat to go behind the couch.

    Then the retard will torture the cat there.

    Why bother having an Animal if your only going to beat it up?

    Small man Syndrome.

  19. The person calling this cruel, retarded, etc knows nothing about cats. The only effective way of training a cat not to do something is to make it uncomfortable or to immediately and consistently frighten it every time it does the undesired action. It's not convenient to put double sided tape on every surface you don't want the cat on, so in most cases, scaring the cat is the only way. Physical punishment only teaches the cat to fear you, not the undesired act. A water bottle only teaches them that no means "Not while I'm looking," the cat will keep getting on the counter when you're not around – just as mentioned above, the cat mostly does this at night when everybody's asleep. If there's any delay between the cat jumping up on the counter and being sprayed, the lesson doesn't connect. Picking the cat up and putting it back on the floor often encourages the behavior as a way to get attention. Noisemakers or water bottles somehow rigged to automatically punish unwanted behavior like entering a certain room or jumping on a counter work wonders – the punishment is immediate every time, and won't teach the cat to fear people.

  20. According to Joshua, who thinks this a cruel way of training your cat, it would be better to take your cat to a therapist where you can all sit and talk about your feelings while listening to a Yanni CD.

  21. I can't stop laughing at the reaction of the cat, crashing into the camera!!!

    Thanks for the laugh.

    And whoever thought this was cruel, grow up!

    Cats don't respond to petting, and childish talk.

  22. For cats, positive reinforcement only works for things they do right. Negative reinforcement only works for things they do wrong. Cats prowl, and their attention is only on what their goal is. No amount of sweet talking is going to keep them from their goal. They are very patient animals, and will just wait for the barrier to their goal leaves (you).

    This isn't cruelty. The animal is not being coerced or forced into the situation. It's the animal's own actions that result in it being scared. Eventually, the animal will try less and less, but due to a cat's nature, he'll always try another angle to achieve the goal, no matter how long it takes. Three possibilities remain.

    1> The cat figures out he's in no danger and just eats the plants.

    2> The cat eventually figures out how to circumvent the camera by moving it and waiting, then eating.

    3> The cat never learns and is a never ending supplier of Internet entertainment.

    Keep it up! Vigilance!

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