Guest Gimmick Posted May 21, 2004 Posted May 21, 2004 I can predict a complete ramble here because this topic is one that I have a passionate concern over: Pet "Immune" Detectors. At the Helpline I co-ordinate my advice is always "adapt the pet around your security, not your security around the pet". Pet Immunity is a marketing gimmick, not a real technological breakthrough. There . . said it and I will probably get hauled over the coals for it, but my opinion is based on personal testing of a number of products in the industry a few years ago. But first, lets start with the electronic principle of a PIR . . . a component inside a detector that reacts to changes in radiated InfraRed energy. This device simply measures the changes in energy focused on to it, through a fresnel lens or mirror. Depending on the depth of processing in surrounding circuity, that signal is then interpreted as "movement" across elements of the PIR component . . and an alarm condition is triggered. It is not possible for a pyro element (the device at the heart of a PIR) to know the size, weight or mass of an object in its coverage area. It is only mearusing radiated energy. A dog wandering around a room could potentially give off the same amount of energy as a man, crawling on all fours. Some manufacturers claim that the lens technology allows the product to "know" that this is a dog "shape" rather than a standing man . . but again, what if the man is on all fours. Is he a dog or not? Pet "immune" detectors operate on one simple principle, the lens (or mirror) is de-sensitised at a certain point, so that the device is detecting less radiated energy under a specific height across the protected area. Generally under about 1.2m high. This is why there is always a "warning" or "recommentation" that the animal is not allowed on to high furniture or up stairs . . . simply because it will then be detected by the normal part of the lens, passing sensible levels of radiated energy. How do I know this? I did tests . . . lots of them. On a board (on a tripod where they were mounted all at the same height - according to manufacturers recommendations), I installed 6 different "Pet Immune" detectors. They were all configured in accordance with the instructions and tested for operation. I then got a dog in (yup . . one that belonged to an employee), and a bag of biscuits. First I proved that the detectors operated as they should (ie; ignoring the dog) by throwing biscuits across the room. The dog walked (and sometimes ran) across the coverage pattern, with no alarms from any of the units. Fine so far . . . I then walked (and ran) across the coverage area, making sure that each of the PIR's generated an alarm condition. Each of them did, which again was fine. I then got down on all fours, and crawled across the coverage area and to my surprise (NOT), none of the PIR's activated. I then got off all fours and hunched my way across the coverage area . . with again, no alarms from any of the detectors. Not so good !! These tests were repeated some time ago in front of the editor of a National security magazine . . and I think I heard his jaw hit the floor. He was concerned but of course a little reluctant to prortray any other stance on Pet Immunity, since the companies involved were "regular advertisers" in his trade press. No comment. It is another ramble (more of a rant) and only my opinion on the matter, but I strongly feel that people need to know how this technology works rather than believing the hype in the marketing material. Pet immunity is simply a standard PIR that is designed to ignore objects (or react less to them) under a specific height across the coverage area. Of course you can all now shoot me down in flames, if you want . . . lol !! Gimmick.
norman Posted May 21, 2004 Posted May 21, 2004 Boom! Nothing is foolproof to a sufficiently talented fool.
Guest Gimmick Posted May 21, 2004 Posted May 21, 2004 I see your "Boom", and I dodge the bullet . . . . swiftly . . . using my new patented Bullet-Proof PIR. Honestly !! It sees the speed of the bullet and signals the control panel to switch an output that turns on a magnet, deflecting the path safely away from me. Fabulous technology and it works . . honest guv !! Just like the "concept" PIR from a well known manufacturer some time ago (nameless of course - I'm not that silly) that could "triangulate the position of the intruder". Nice !!
Service Engineer Posted May 21, 2004 Posted May 21, 2004 I have to agree with Gimmick, we have tried all sorts of these pet detectors and most have worked great with Doggies, or anything that stays low, but bring in a cat and its another story (cats climb). There`s virtually no chance of these detectors picking up anything that stays less than 3 feet from the floor, and more than 6 feet from the detector, including Humans...... ........................................................ Dave Partridge (Romec Service Engineer)
breff Posted May 21, 2004 Posted May 21, 2004 Yet another agreement- I tell people that they basically ignore anything below approx 1 metre and dont recommend them.....................Having said that I have Visonic K980s in my house, but only as back up for the Impaqs on the windows. The opinions I express are mine and are usually correct! (Except when I'm wrong)(which I'm not)
engineery Posted May 21, 2004 Posted May 21, 2004 i have also got to agree with gimmick, i don't recommend them and will always explain to the customer how they work and that they are not likely to pick much up below a certain height stephen Any comments / opinions posted are my opinion only and do not represent those of my employer or Company
Woosh Posted May 21, 2004 Posted May 21, 2004 Dont laugh I promise this is true one mf my customers insisted on pet pir's and he has 2 cats :!: :!: :!: I warned him told him on his head be it and fittec Visonic K9-80 and guess what only 1 False alarms in 6 months. Either he is telling lies of something is funny. I agree with all of you avoid like the plague.
Guest securityconsultant Posted May 21, 2004 Posted May 21, 2004 More of the same pet immune comes at a cost of detection loss that said I'm a lazy bugger at times so when we got our cats I just swapped for k980s they work ok no false alarms and I've still got a tv
neil.c Posted May 21, 2004 Posted May 21, 2004 Cats and dogs have higher body temprature than humans so said Pir's may be less sensitive also to reduce the risk of a pet "false alarm".
CompostCORNER Posted May 21, 2004 Posted May 21, 2004 K980's were used by my former company and they were quite successful. We never installed them in houses with cats though with their 1.8mtr minimum safe distance seeing as cats have the potential to dig their claws in everything and anything and get within that range. k980's though are very much more asthetically pleasing compared to the older method of installing a conventional pir, upside down at 3 feet off the floor. Plus K980's give some coverage to the floor where-as the older method didnt. My present employer will not deal with any pet immune detectors due to the precise install methods and the frequent return visits. Tony
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