Automated hose keeps cats from watering you

Commenter [TheCreator] reminded us of this fantastic video from [Craig Turner] who you may recognize from SBS’s Top Gear Australia Video Competition.  You see, [Craig] has been struggling for some time with the problem of neighborhood cats relieving themselves pretty much all over his stuff. Through surveillance he identified (and named) around 9 separate cats sauntering into his yard during the wee hours of the night.  The only issue now was to humanely discourage them from entering his yard.

The best solution, in this case, was a simple spray from the garden hose, but who is going to stay up all night to watch for cats? [Craig]‘s ’75 Galant happens to have aftermarket door locks. These typically contain a simple powerful 12V actuator that will push or pull when given current. The actuator is strong enough, and has enough travel, to depress your typical garden sprayer handle. The lock actuators even include enough mounting hardware to tack everything together.  The only irreversible part of the hack appears to be the hole drilled into the sprayer’s handle.

The job of cat detection is handled with a PIR sensor (sourced from his home security system) and a paper towel tube to narrow the detector’s field of view. Placed at animal height the PIR detector works like a trip line, and flips a relay connected to an array of devices:  A bright LED lamp, a DSLR set to take several quick photos of the victim, An HD video camera, and the sprayer solenoid.  This whole rig is placed at a convenient choke point and hilarity ensues! A schematic is included in the video but is pretty difficult to interpret, we transcribed it for you. Some details are unclear but essentially a few relays are stapled together to provide either high or low switching signals.

Check out the video, [Craig]‘s schematic, and our interpretation of [Craig]‘s schematic after the jump!


  1. Tech B. says:

    I just posted this on Facebook yesterday lol. I found it via; great website to pass the time.

  2. NK says:

    Hey guys, are you playing with the websites themes-backgrounds?

  3. BiOzZ says:

    haha my friend linked me on youtube

    WTF happened to the awesome looking site?

  4. dmcbeing says:

    This has to be the best hack video i’ve ever seen on hack-a-day ever :D.

  5. Kibodwin says:

    I need something like this and was thinking
    of solenoid and a pan tilt hooked up to
    a garden hose. Then have a webcam detect
    motion and have the pan tilt spray that area.
    I found lots of info on the needed bits here
    it is just a matter of putting it together and
    testing. I also have foxes which if I could
    leave alone would be cool.

  6. dmcbeing says:

    That H??? relay should be Horn relay according to the video.

  7. xorpunk says:

    nice way to drive a ten cent nail with a 20k hammer ^^

    You could of done this with under ten dollars in electrical components and garden hardware..It wouldn’t of been millionaire style I guess..

  8. NeatBasis says:

    That last cat’s like auditioning for the next matrix movie. :D Really cool hack.

  9. PoisonWaffle says:

    Friggin’ awesome idea, and a great video!

    Totally subscribed to the dude. Props!

  10. Morgauxo says:

    Ok that is awesome. Did you really disable your car and home security system to do it though? You might want to check out your local junkyards and/or Ebay!

  11. TheCreator says:

    Love it.

  12. Queeg says:

    I wonder if the cats would learn faster if it triggered a paintball gun instead of a hose.

    Only one way to find out.

  13. The DON says:

    I laughed so hard I cried.

    Awesome video.

  14. Keith says:

    Love the disclaimer at the end of the vid. And here I thought just the USA had irresponsible pet owners. Guess they are everywhere.

  15. Matt says:

    HAHAHA classic, love it. Could have hooked it up to a different type of trigger. Paracetamol (Tylenol) and tuna works also. Personally I have a low lying electric fence round my garden. Mint Galant too!

  16. sean says:

    My stomach hurts from laughing so hard!

  17. James says:

    @Matt – pathetic person you are.

  18. anonymouse says:

    @matt – I can’t believe you’re suggesting poisoning people’s pets.

  19. leniu says:

    I have that same problem with dogs. I must tray it :)

  20. PocketBrain says:

    “the wee hours…” HAA! I see what you did there!

    Seriously, I have considered hooking up my sprinkler system to a motion detector. That @#$& neighbor’s mutt keeps paying my lawn a visit. It just ain’t right.

  21. Elias says:

    Hilarious video :D

  22. Fileark says:

    What a terrific vid! Its hacking and funny cats, can’t beat it.

  23. supershwa says:

    Hahahahahaha can’t hahahahaha stop hahahahahaha laughing hahahahahahahahaha

  24. MrX says:

    Wow! The build is quite simple but it sure works. And the way they put it in the video is really a success! I love it! :D

    I beg for a improvement now. Maybe add some pan tilt mount with a IR camera and hose attached. That should teach them :)

    I would also replace the mechanical relay with a electronic one cause I think the cats might be hearing the “click” which is giving them some precious time to start jumping.

  25. miked says:

    I though of this one used for deer:

    This post reminded me to look for the deer deterrent for my sister. She has around a dozen deer in her yard every night eating up the garden, shrubbery, flowers, etc.

  26. menotme says:

    two words…coyote urine

    though I love a good cat foiling

  27. Hirudinea says:

    Everybody loves a wet pussy but did he have to disassemble his car to do it!? (But then again considering the car, that was probably the best use of it.)

  28. Stevie says:

    There’s been some really great stuff on HaD this week. Nice one!

  29. Stevie says:

    The idea seems solid enough but did it really need to be such high pressure? I think it would be more humane and just as effective (or ineffective as the case may be) to spray water at them at a much lower pressure.

  30. CatEater says:

    They still have fur on them. I say the pressure isn’t high enough.

  31. salomon says:

    I just cant stop laughing! OMG this is one of the funniest videos I’ve ever seen.

  32. Digital says:

    this isn’t exactly a new idea, I saw almost the same thing YEARS AGO!

    very funny regardless. Love the names of the cats!

  33. rossmarsden says:


    And the first time I have heard “solder” pronounced properly in projects featured on this site.

    Sodder? What is sodder?

  34. Ashish says:

    Looks awesome, but his website seems to be down because of all the traffic.

    Well, that’s the downside of getting featured on Hackaday. :)

  35. monster says:

    that was a lot funnier than i was expecting a build log to be

  36. JDN says:

    The video’s well done and fun to watch.

    For controlling the water, I’d recommend a solenoid valve from an old washing machine. Even new, I can’t see that costing much.

  37. Nicholas Farshidmehr says:

    I would just stay up all night and shoot the cats.

  38. @ Matt, you know that is fatal at human doses, right? That’s a felony, and if caught you’d get more TV time than killing a person in most cases.

    I think the point of this was to NOT kill them, but really %#$@ with them without any harm (other than the cat itself trying to GTFO).

    I started laughing at “wee hours of the night” in the HaD description.


  39. Whatever says:

    That’s awesome! Great video and presenting, I laughed my ass off!

    Now regarding the motion sensor, most of them are simply closing a relay when tripped. No need to solder into the LED. 60€ for a state of the art Honeywell motion sensor, new. Probably less pricey than disabling a zone on the alarm panel of your house :)

    And if I left a couple of cameras in my yard at night, they’d be stolen in the next hour.

  40. Jesse Congdon says:

    @KanchoBlindside, I have to admit, it was a happy accident :)

  41. Ink says:

    My dad actually set up something like this years ago. He wired several of the motion detectors (which he took off of the motion lights) into one of the sections of our sprinkler system. It was to keep the dogs from digging on the yard and worked rather well. Anytime the dog would walk on the yard the sprinklers would turn on until they walked off of the yard. Only problem was that sometimes a bird would fly by, or on windy days the trees would sway back and forth causing it to go off all the time.

  42. Igor Peixoto says:

    Awesome! Every hack should come with a video like this, LOL

  43. Reza says:

    Hackaday is screening my emails. I sent this link in 2 weeks ago and they ignored it.

  44. Marius says:

    Good stuff. I could not stop laughing :) thanks!

  45. cyplesma says:

    didn’t read all the comments, but you can always use the 120 ac volt controlled water inputs of a washer. hook up the main line to the common of the control and you can control the outputs with 120 volts ac. It gets you two outputs. Can be easily scaled up.

  46. Don says:

    You can buy a device that has the pir and valve already. Called a scarecrow. Otherwise a valve from a sprinkler system would be much more reliable.

  47. Craig Turner says:

    Hey, awesome write up! best description I have seen! and nice work with the interpretation of the schematic. My mock up was mainly for entertainment purposes so it is a little misleading but you have encouraged me to draw it up properly when I get a chance and I will put it on my web site.
    FYI for anyone interested for now, in short;
    Basically every device had an independent power supply (battery & 240 volt) other than the actuator and relays. The HD cam was independent running to a DVR card with motion detection via software, thus to allow pre roll on the video. I also used a timer kit to allow the LED lamp and shutter switching on the camera to stay on a few seconds after the spray finished. The LED lamination time on the PIR was perfect duration for the spray duration though.
    Thanks for posting and I will try and get some details up online for those interested.
    Craig Turner.

  48. Jesse Congdon says:

    Hi Craig! I couldn’t fit the cat in the drawing though, making my interpretation wildly inaccurate. Also doesn’t that PIR detector already have a relay (or opto isolated switching circuit)? No need to waste precious angle grinding time at the soldering station. The AC cable was also reduced ’cause I had no space, 470 pixels wide is tiny :( Oh I think the lamp is a bit messed up too in my drawing (no ground for the switching signal input), anyway the idea is there! That video is a feat of tongue-in-cheek hacking we can’t wait to see more!

  49. Smaug says:

    I can’t stop laughing!! It’s beautiful!!
    I made years ago an wire electrifier with a motorcycle HV coil to stop the cats to enter my property. It was also funny, and in a couple of days no cat was brave enough to repeat the experience.

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