We have been in our new home for 5 weeks now and it has an alarm system. We have just got a cat too. I’ve noticed that we set off the sensors all the time, but will the cat if we set the alarm when we leave the house? (there is a cat flap for him to use so he can come and go at will).
I had the same problem, although our cats were strictly indoor cats. Check your alarm manual. You may be able to set the system to protect the outer perimeter (windows and doors) without setting the infrareds inside. After all, once a burglar has set off a door or window sensor, it doesn’t really matter if he’s set off an interior infrared.
Believe it or not, when my mother in law was overseas, we got called to their house because a spider had set off the internal IR systems… so yes, unless you can change it to ignore the IR sensors, I guess the cat will set the alarm off.
It was not a large spider, but it was spinning it’s web down from the ceiling about 4-5 feet away from the sensor. We did not know it was a spider at the time we went there, so we were rather relieved actually.
When I was shopping for an alarm system, alarm companies told me they could work around a dog, but cats jump up on things when you’re away. If you set the motion detectors high enough to miss the cat, you’d miss the burglar. I had to go with other triggers.
When we bought our house, we had an alarm system installed. There is a motion sensor aimed at the bottom of the basement stairs. The cat has never set it off (and her litter box is in the basement), but apparently, a pair of my daughter’s pajama pants did when she tossed them down the laundry chute last week.
These things can be calibrated so something the size of a cat won’t set them off, and usually installed so that the animal won’t be so close at any time so as to appear larger to the sensor. But it would probably take a professional to work it out.
I used to install alarm systems for a living.
Yes, cats cause a lot of false alarms. Apart from careful positioning the passive-infrared detectors, believe it or not we used to mask off the lower parts of the detectors so that they were blind to any activity below a certain level. You have to determine the highest part a cat can get to and use that as the threshold. The most common spot was the back of the couch on a wall facing a PIF. We’d use adhesive labels cut to size, and adjust them as necessary. A low-tech solution, but it worked.
Not on-topic, but the most common source of false alarms are those stupid “window-bugs” that detect vibration on a windowpane. They’d go off if a truck drove through the neighborhood.
You should be able to “shunt” your alarm, which means turning off the motion sensors, and relying on the door and window sensors for security. Some ADT alarms have a “MOTION OFF” button you can press when arming the system, or a button lable “SHUNT” on other systems. Call your alarm company to ask them. This command is only temporary-- you can use the alarm “regularly” whenever you wish.
This is what we do, since we have a dog. The alarm will sound if any door or window is opened, but the dog can romp freely. We use the “regular” alarm with the motion sensors only when we go on vacation.
My wife and I have three cats that have the run of the house (including jumping on the kitchen counter when we are not around, they love it up there! Bad Kitty!).
Our alarm system has a motion detector that covers the kitchen that has never been tripped by our cats. I, being the curious type, did set it off while crawling on the floor, so it cannot be height sensitive. It must be size sensitive.
Motion detectors are heat sensitive. Typically they are looking for radiant heat — infrared energy with a wavelength of around 10 micrometres, (give-or-take three or four) which is approximately what you’d expect for body temperature. These types of motion detectors, (passive infrared detectors,) use a simple lens to focus on a couple of IR sensors. When each sensor reports a positive reading in sequence, the unit infers a moving body. This way, you don’t get a false alarm when the sun heats your livingroom wall up to the “trigger” temperature.
It’s very common for PID’s to look for a wide enough spectrum that pets can set them off. The best solution is to position them so that they’re looking at an area which must be crossed for a person to gain entry, but a pet can’t get to. Limiting the vertical scope of the detector is the easiest way to do it.
More “accurate” sensors, that look for a temperature reading that is typical for a human being, but not for a smaller animal, have their drawbacks, too. A very narrow trigger area would allow a canny burglar to camoflage their IR signature… either with an insulated suit, or say, by taking a whole bunch of niacin before they did a B&E, to temporarily raise their body temp. (This approach would depend on knowing that the house had a “pet-friendly” motion-sensor, and getting past the non-IR stuff, like magnetic contact-switches a door or window. Unlikely that a thief would take such pains, though, since thievery is generally the province of stupid folk. But it would be neat for the purposes of a mystery story.)