Cat Detector

C

clockwork

Member
Hi There,
Now I no longer have a dog to carry out the work I wish to make a picaxe controlled device to prevent the local
cats from using my front and rear gardens as a loo. I am prohibited by my wife from using the more robust methods
of prevention like a 12 bore, traps or even bricks dropped from a height (not that I own any of these items, but no doubt
could aquire a brick or two quite easily).

So what I would like to ask anybody with practical knowledge of such things the following:-

1/. What is the best way to detect a cat, both at night and during the day? What sort of range is possible?

2/. I am considering Ultrasonic transducers, but can a Cat hear sounds up to 40Khz? If they can could this
this frequency be used to deter them?

3/. How effective would a P.I.R. detector be? Would it work in daylight?

4/. I am considering using flashing LEDs to mimic an animals eyes to act as a deterent, is this effective?

5/. Using water jets to deter the little beasts is an appealing solution but I would like to have a small self contained
unit that does not have trailing hoses, so is there any other way (thats legal) to provide a effective deterent?

Many thanks Clockwork
 
N

NoEinstein

Member
clockwork said:
...

3/. How effective would a P.I.R. detector be? Would it work in daylight?...
Click to expand...
Too bad the 12 bore is out of the game. Anyway, I'm sure most PIRs could detect a cat and I'm sure they would work in the daytime. I've set up "Bear detectors" in the forest and found they are also very good at detecting squirrels at maybe three meters or more. You must be aware, however, that PIRs detect changes in IR, so flickering heat sources, for example distant campfires, etc. can sometimes set them off. Also being close to bodies of water, such as lakes that might ripple distant heat sources (hot factories, distant fires, etc), can also sometimes set them off. PIRs are probably fine for residential use.

Adding a bit of mild ammonia-based window cleaner to your water spray might help convince the cats to lurk elsewhere.

But, you know, getting another dog might be a good idea, too.
 
D

Dippy

Moderator
Have you tried the granular smelly stuff which claims to repel cats and dogs?

Hose pipe? Lawn sprinkler?

My neighbour, a pidgeon person, has a cat & dog repeller which emits a high-ish frequency warbling sounder.
No way ultrasonic. Sounds well below 10kHz. It randomly sounds for a few seconds at a time every now and then during the day.

He's an intelligent bloke and says he has a reasonable success.
And he's intelligent enough to know that if he carried out any 'oh so big and macho' actions with a weapon or chemicals that he'd have a visitor knocking on his door a few days later...
 
T

TheChief

Senior Member
I would suggest getting another dag.
You will not realistically be able to sense what you are attempting to deter. Best solution would be the likes of a laser scanner which you could program to detect certain "sizes" and changes in field but these run at a few K as far as I remember eg the company "SICK".
In any case it's moot how the data is acquired but something as sophisticated would at least be required for such a project. Unless maybe you could measure the effective capacitive change on the lawn as a ground plane and grid ref that to a servo to fire a "missile"?
 
J

Jeremy Harris

Senior Member
ZOR said:
Glad your not next door - RSPCA
Click to expand...
Since when have the RSPCA had a problem with electric fences? The voltage may have been high (just as it is with any electric fence), but the current delivery capability of a motorcycle coil is tiny. As the old saying goes, "it's volts that jolts, but mils that kills" (referring to the milliamps that need to flow through the heart conduction system to make it stop).

The fact that the cat walked away and lived on is evidence that no harm was done.
 
Z

ZOR

Senior Member
I saw the cat afterwards, it had one eye up the other down. Only joking.
It would be good to have a reference library of projects for Cats, Dogs fowling, Dogs barking, Pigeons, herons. Not so worried about bears in the UK.

Have you tried peeing around the garden, I think I heard that was a good barrier. Don't let the neighbor see you doing it

Regards
 
P

Paix

Senior Member
Dippy said:
Have you tried the granular smelly stuff which claims to repel cats and dogs?.
Click to expand...
Would that be the 12 guage lead pellets with gunshot residue?

I think that the statistics suggest that the RSCPA put down an awful lot of cats and dogs. They also release foxes illeagally and on private land belonging to others. I read recently of a farmer who was not impressed with this behaviour and offed four foxes on his land that had just been released. They were not amused, despite the fact that it is not legal to release foxes or other vermin in this manner. What I say is, What about the chickens!
 
K

Kecked

Member
Cats are by nature curious if you can lure them into a have a heart trap you can catch them till you can then release them later. This will after several attempts sink into the cat who will be scared of you and your yard for life. No real harm done. Same method they used to use on young boys by tossing them in jail for an afternoon. This is the scared straight method for cats.

If that fails, (now in the joking section), get a motion detector and gut a microwave oven. Cut a horn waveguide and use IR to track the cat with servos. Emit just enough energy to make it feel the heat. Hey it works for the army.
 
S

SAborn

Senior Member
Where can i get some cat " pro-pellant" now that looks like a fun project, although it will require a picaxe tracking device to locate your cat after launch.
Puts a new meaning to "SuperCat"
 
D

Dippy

Moderator
Actually, if you adjust your RF frequency you can resonate at a particular frequency which disrupts neurotransmission.
Far better than warming people up or 1970's tasers.
 
W

westaust55

Moderator
clockwork said:
3/. How effective would a P.I.R. detector be? Would it work in daylight?
Click to expand...
The PIR devices typically used for home and office security systems are not likely to work in daylight due to IR heat from the sun.
Even for indoor use many PIR installation sheets recommend mounting so as not to be facing in the direction of a window to prevent "false" alarming.


2/. I am considering Ultrasonic transducers, but can a Cat hear sounds up to 40Khz? If they can could this
this frequency be used to deter them?
Click to expand...
Seemingly cats can hear up to 64 kHz (dogs to about 45 kHz). See http://www.lsu.edu/deafness/HearingRange.html
 
N

NoEinstein

Member
westaust55 said:
The PIR devices typically used for home and office security systems are not likely to work in daylight due to IR heat from the sun.
Even for indoor use many PIR installation sheets recommend mounting so as not to be facing in the direction of a window to prevent "false" alarming....
Click to expand...
I'm not sure but I think that they mostly mean to avoid direct sunlight, not daylight conditions in general. After it passes through a window, direct visible sunlight could be converted into heat around the PIR itself and simply saturate it. IR at the PIR band does not pass through glass or many clear plastics very well. I've never been able to get a PIR to detect a person through a window, for example. Which might explain why the PIR lenses are a cloudy polyethylene instead of clear polycarbonate or something else. One reason you might avoid aiming a PIR at a window even indoors might have to do with how wind causes windows to slightly warp, in which case they are continuously changing their reflections, so if there are any heat sources inside the house, their reflections might appear to be changing positions, which is the sort of shift that sets off a PIR.
 
D

Dippy

Moderator
Like a lot of things in life, sensing things properly requires a good signal:noise.
Even if the sensor is relatively insensitive at optical bands it can still overload/upset a PIR.
So, as you say, direct sunlight is the worst.

Security installation instructions sensibly want to reduce the probablity of incorrect sensing.
Aiming at windows, fireplaces, radiators, heating ducts etc. are considered less than ideal.
PIR sensing can work in daylight but , typically, at a far reduced sensitivity (and often reliablity too) compared to night time (esp a cold night).

Yes, at far infrared polyethylene is transmissive. Whereas glass and many common 'clear' plastics aren't so much.
Many window double-glazing glass panes have a coating to reflect the far 'heat/greenhouse' IR back into the house (e.g. Pilkington).
Get a thermal camera and aim it at someone wearing glasses - they often look like a panda.
Polyethylene lenses are often used to focus certain microwaves.
 
R

rossko57

Senior Member
Purpose made detectors for external day & night do exist
http://www.gjd.co.uk/products/wired-detectors/d-tect-dual-tech/
Not particularly cheap. Unfortunately they're aimed at people detection, and so far as possible the makers de-tune them for "pet" size targets. They claim ~30m range but I think you'd need to de-rate to say 10m for cats

The most reliable outdoor detector is the fixed IR break-beam, if you can identify suitable locations(s), up to 100m is easy peasy.

Dunno what you might use as the response/deterent though. I don't think the twinkly eyes business will do it - that may alarm 'prey' species, but not a smart predator like a cat.
 
C

clockwork

Member
Thankyou to everybody that contributed. I will now start experimenting with a PIR rescued from my junk box (component storage system) to see if it can detect the dreaded moggies particularly in daylight. Failing that I may have to resort to more robust methods. Unfortunatly the more robust the method the more illegal some seem to be. I have already tried chemical methods, none of the commercial products seem to have much effect.

I cannot use loud noises to encourage the moggies to go somewhere else as my next door neighbour needs little if any reason to complain as it is.

So more experimentation is required. Again many thanks for all the information. Clockwork
 
W

westaust55

Moderator
boriz said:
"I cannot use loud noises "

Remember cats can hear frequencies that humans can't. A big tweeter and a 20kHz tone should work. Something like this: http://www.ebay.co.uk/itm/PULSE-TWEETER-HORN-MODEL-PLS-00309-NO-DIAPHRAM-PAIR-/261119147617?pt=UK_ConElec_SpeakersPASystems_RL&hash=item3ccbe9fe61
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From my knowledge and as per the webpage I gave a link to at post 17, younger persons have hear up to 20 kHz (and seemingly to around 23 kHz) so a 20 kHz tone might keep the kids awake/annoyed (except those with earphones permanently plugged in any suffering early deafness).
The 40 kHz transduers was a possible option.
 
K

kevrus

New Member
I had two 'ultrasonic cat deterrents' in my garden. They did nothing to deter the cats..in fact, one cat used to hang around in front of one of the transmitters, constantly activating it. Changing the frequency did nothing. however, I did get a complaint from the neighbours daughter whos bedroom overlooks my garden. She could hear the tone regardless of the set frequency, and found it quite unpleasant. It was audible to her even with windows closed and a tv on or some music playing. They didn't work for me.
 
J

Jeremy Harris

Senior Member
I can confirm that ultrasound isn't effective.

One of my early attempts used a piezo horn speaker, one intended for use with PA systems (I think it came from Maplin, years ago). This was quite large, and was running a swept tone from around 20kHz up to around 25kHz, driven by a simple complimentary output stage and a couple of 555s. The power level was fairly high, probably of the order of a couple of watts, yet the cat would wander around in front of it, completely oblivious to the noise, it seemed.
 
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C

clockwork

Member
Thanks for the information re ultrasound. So thats one solution to cross off the list. I am now wondering if a portable garden spray (that you pump up to create the pressure) may make an effective deterent, the sort you can use to spray roses and things. This may be the answer. Just need a solenoid strong enough to operate the valve mechanism but still work using a small battery. It may be that the battery would have to be a small 12 volt rechargable type. This solution would be bigger and more expensive but will it work ? No doubt the spray head may need to be modified as otherwise there would be little chance of hitting a moving moggie.

Clockwork
 
J

Jeremy Harris

Senior Member
I've got some 12V solenoid operated water valves going spare if you want one. They draw around 250mA when on, but you may be able reduce this a bit by adding a series resistor to limit the current, with a big capacitor across it to allow full current to start (or you could use a couple of Picaxe pins to do the same thing). They originally came from RS more than 20 years ago (but rather amazingly are still listed by them: http://uk.rs-online.com/web/p/process-valves-solenoid-operated/0342023/), and have threaded ports that are the same as those used on washing machine water connections. PM me your address if you're interested and I'll pop one in the post, free gratis.
 
S

SAborn

Senior Member
I would think it best to use mains water and a impact sprinkler, the type often used on schools and ovals, the ones that go... Choo, choo, choo, ...... Charrrrrrrrrrrrrrrrrrrrr....... as they reverse back on the set arc, it dont need to be on for long as the spray of water and the mild racket would upset any moggie, looking for a quite moment to commit a sin in your yard.

You could get a cat of your own, as then it will mark/claim the territory as its own, as at present you have neutral ground for the claiming by the strays.

Perhaps a good cat to consider for a pet might be a Panther or a Lion.

EDIT...

It may have been listed already, but a thread some months back covered a similar topic.

Here... http://www.picaxeforum.co.uk/showthread.php?20176-How-to-stop-cats-peeing-on-your-car&highlight=cats


And the first link in the thread ..Here... http://www.youtube.com/watch?v=uIbkLjjlMV8&feature=share

I think is priceless, and a must see, then perhaps its just the sense of humur of the maker i find interesting, Either way its all harmless revenge that i think you are looking for.

The comercial product in the second link to the thread uses a impact sprinkler.
 
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K

Kecked

Member
Ultrasonics at 22khz are suppost to disrupt the nervous system. Information Unlimited has kits that put out 130db or so. If you sweep the frequency it would be even more annoying. I suppose you could make a device that has so much directed energy it kills the animal or makes it deaf. If you screw up a kid with this you would have a real problem. How about a good old fashion fence.
 
P

PerthEng

Member
There are means that do not involve sound, high velocity metal particles, traps, sprays and the like, using common items we humans consume that could ensure a cat does not return without the need to clean up cat doo or deceased cats from your property.
May still be seen as socially unacceptable so I have sent a PM to the clockwork on such a solution.
 
S

SAborn

Senior Member
Here in Adelaide the council brought in a regulation that cats need to be under house arrest, any cat trapped on other peoples property can be taken to the council for destruction, if the cat is microchipped then its returned to the owner with a heavy fine, otherwise it is destroyed as a stray or feral cat.

I think the house arrest regulation only apply to after dark, when most cats are turfed out for the night and are most active, the average cat naps most of the day then prowls all night.
 
JimPerry

JimPerry

Senior Member
My solution is Dobbie the Dalmatian and Velvet the Dachshund - Dobbie catches cats in mid air when they climb the fence and Velvet gets the rats at low level.

Problem is that Dobbie doo is more than cat doo :rolleyes:
 
P

Paix

Senior Member
SAborn said:
Here in Adelaide the council brought in a regulation that cats need to be under house arrest, any cat trapped on other peoples property can be taken to the council for destruction, if the cat is microchipped then its returned to the owner with a heavy fine, otherwise it is destroyed as a stray or feral cat..
Click to expand...
The Adelaide council are obviously pretty much anti-cat and are happy to share their distaste with residents. How long before there is a backlash when the tide of public opinion decides that the scheme is either barbaric or just punative?
 
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