Hi,
I have just built an open deck on the back of the house. The deck has a roof so the two upholstered chairs are protected from the rain.
Unfortunately this makes an attractive shelter for stray cats who choose to sleep on the chairs most nights. I want to persuade them to go elsewhere and short of getting a dog, I am intending to build a detector that would make a sound (maybe a dog bark) when a cat climbs up to a chair.
The cushions are too thick for a weight sensor.
I was considering a photocell above the top of the cushion but it has to work in the dark.
Can some kind person please provide a circuit that would work and is not too difficult to build.
I have not done electronics for several years.
Thank you in advance.

 

Does this have to be electronic? A mousetrap or two in each seat will scare them into not returning. I mean the old fashion spring type traps, no need to bait them.

 

Does this have to be electronic? A mousetrap or two in each seat will scare them into not returning. I mean the old fashion spring type traps, no need to bait them.

That's the way I once trained a cat to stay away from the HVAC registers. I placed the traps upside down so that they didn't hurt the cat, but startled him when they went off.

Electronically, a PIR detector might be a good choice.

 

I agree with the PIR approach. Mine are sensitive enough to be triggered by cats. In fact I use one in my basement to light up kittyland whenever they need to eat or use their box at night.

I'm pretty sure a sound or light alone won't deter a cat, unless the noise is bad enough to also bother your neighbors. Even my local raccoons don't give a hoot about the light coming on. Maybe turn on a radio?

And you MUST watch this. Not optional.

 

I bought some of these. They work well and are certainly cheap enough, but of course, delivery takes about three weeks.

 

http://projectsentrygun.rudolphlabs.com/

 

Thanks for the replies. I enjoyed the one on you tube about the water cannon but I can't see the wife going for me ******* on the chairs, even if she did the video taping.
The one about PIR's on Ebay was interesting but I would still need a circuit. Does anyone know of a circuit that would do the job?
Thanks.

 

 

Thanks for the replies. I enjoyed the one on you tube about the water cannon but I can't see the wife going for me ******* on the chairs, even if she did the video taping.
The one about PIR's on Ebay was interesting but I would still need a circuit. Does anyone know of a circuit that would do the job?
Thanks.

Interfacing to a PIR is relatively easy. Here's a test circuit that I built to test the PIR and light some LED's when the PIR was activated. The same arrangement could be used to turn on any device that will run on 6V at something less than the BC547's maximum sustained collector current of 100 mA. Additional or different transistors could be used if more current is required.

ETA: I just checked and the PIR will run on anything from 4.5 to 20 VDC, so there is plenty of flexibility there.

 

Aww that's so sweet! I love cats too, got a little black/brown and white cats called Guinness myself

 

If you google toxoplasma gondii and you still like cats, then YOU ARE INFECTED!
You are under my coooooooontroooooool! Miaow!

 

If you google toxoplasma gondii and you still like cats, then YOU ARE INFECTED!
You are under my coooooooontroooooool! Miaow!

I googled it and it hasn't put me off cats... fortunately my cat never uses his litter box.

 

If you google toxoplasma gondii and you still like cats, then YOU ARE INFECTED!
You are under my coooooooontroooooool! Miaow!

It's too late; I already have it.

It may be too little sleep, but the last one on the list is really amusing. Is it me or the new cat that shouldn't be pregnant? And how new does the cat have to be? So, it's ok to get an old cat as long as neither one of us is pregnant?

 

I googled it and it hasn't put me off cats... fortunately my cat never uses his litter box.

Are you keeping your outdoor sandbox covered?

 

Are you keeping your outdoor sandbox covered?

Haha, too old for one of those! Besides... he knows not to go on his own doorstep or back yard!

 

Will these work on coworkers that talk incessantly about politics as a matter of fact instead of a matter of opinion? I need something to drive them off so I can get some work done! Maybe I'll try the paint-ball gun approach which would be extremely ironic!

(I'm not hijacking - this is very tongue-in-cheek!)

 

How about a cat repeller circuit using ultrasonic sound waves , best frequency is 30-32Khz as it peaks then.


use a circuit like these

http://www.circuitstoday.com/wp-content/uploads/2009/03/electronic-mosquito-repeller9.jpg

http://s2ptech.blogspot.co.uk/2012/03/electronic-mosquito-repeller-circuit.html#.UZY2GKLFXEE



alter the resistor /cap values to get 32 Khz approx.

 

How about a cat repeller circuit using ultrasonic sound waves , best frequency is 30-32Khz as it peaks then.

I didn't know snake oil worked as a cat repellent.

 

You really doubt it that much Ernie?

Cats are intelligent and have superb hearing, and suspicious, sensitive personalities.

I would think a really loud irritating ultrasonic noise, that triggers when the cat tries to enter the area (or remains in the area), would be an excellent deterrent.

That doesn't mean that every "ultrasonic cat repeller" on the internet is going to be effective, but I'm sure you COULD make one that works very well.

 

I'm not that convinced that cats have hearing so much better than our own. Cats DO pay attention to different things than we do and are not as distracted by the things that capture our attention.

I've played around with tone generators on the computer to test hearing response of the humans in the house. The kids in school had fun using a phone ring tone that their teachers cannot hear. I was skeptical that it worked but of course my testing showed that it worked great. 12 kHz I think will draw the line between the over and under 30 groups.

Anyway, my two cats didn't seem especially annoyed by the high frequency tones that I couldn't hear, whereas the lower tones or a harmonica drives them crazy. They react mildly if I blow a dog whistle. Certainly they are not driven away by it.