Short answer
If there is a cat or dog at home, a pet-immune motion sensor is chosen, and it is mounted at the height the manufacturer specifies, facing the right direction. These sensors ignore animals under a certain weight, but cats climbing on furniture can exceed the limit. The most reliable solution is to protect doors and windows with contacts and to disable the motion sensor in the rooms where the animal roams using partial arming.
Why does a motion sensor mistake an animal for a person?
The motion sensor most used in homes is the PIR type. PIR detects the movement of heat differences in the room. Every living thing with body heat leaves a trace in the area the sensor sees as it moves through the room. The sensor cannot tell by itself whether this trace belongs to a person or to a cat.
An ordinary sensor cannot tell a medium-sized dog walking around the living room from a burglar. When you arm the system at night and go to bed, the siren sounds the moment the dog goes to the kitchen for water. After a few nights like this, many families stop arming the alarm. A system that was paid for and installed becomes unused. The aim of this article is to prevent that.
How does a pet-immune sensor work?
In pet-immune sensors, the lens and the software are designed differently. The sensor sees the zone up to a certain height from the floor with less sensitivity and ignores the movement of a small heat source. An adult person is detected because they leave both a taller and a larger trace.
Manufacturers state in the catalog up to what weight these sensors ignore animals. This value varies from model to model. When choosing, compare your own animal's weight and size with this value. If you have two dogs running side by side, the sensor may see them as one large creature; take that into account too.
Some models use two different detection techniques together. These so-called dual-technology sensors measure movement with microwave as well as PIR, and wait for both techniques to trigger at the same time before raising an alarm. They reduce the risk of false alarms but do not solve the pet issue by themselves.
Why do cats make it harder?
A pet-immune sensor assumes the animal moves around on the floor. Dogs mostly stay on the floor. Cats, however, climb on the back of the sofa, on top of the fridge, onto the bookcase. A cat that climbs high enters the zone where the sensor is fully sensitive, and in the sensor's eyes it is no different from a person.
A bird cage, an aquarium heater and a radiator that falls within the sensor's field of view can cause a similar problem. Before installation, check whether there is a surface the animal can climb in the area the sensor will face. If the bookcase or the scratching tree is moved, the sensor's position should be reviewed as well.
Expert note: Position the motion sensor to face not a piece of furniture the animal can climb, but a corridor that passes beside the furniture. A burglar has to pass through that corridor when entering the room, while the cat usually stays on top of the sofa.
- Pet weight below the sensor limit
- Mounting height as per the guide
- No climbable furniture in the field of view
- Not facing the radiator or air conditioner
- Contacts on doors and windows
- Partial arming mode set
- Walk test done with the pet
Correct installation: height and direction
For a pet-immune sensor to work, you need to follow the mounting height the manufacturer recommends. If the sensor is mounted too low, it sees the animal head-on; if too high, the lens calculation is thrown off. The height value in the installation guide is not a suggestion; it is the condition the sensor was designed for.
Placing the sensor at an angle where the animal passes in front of it from the side, not walks toward it, makes detection more predictable. Stairs should not be in front of the sensor; an animal climbing the stairs appears closer to the sensor and higher up.
- Follow the mounting height stated by the manufacturer.
- No sofa, bookcase or stairs in the field of view.
- Do not face a radiator, air conditioner or sunlit window.
- Keep the animal's bed and food bowl outside the area.
- After installation, do a walk test together with the pet.
Contacts and partial arming: a pet-friendly plan
In homes with pets, the most reliable method is to move the protection to the outer shell. Magnetic contacts on the entrance door, balcony door and reachable windows are not affected by animals. A burglar has to open one of these to get in, and the alarm sounds before a step further inside.
Partial arming means the panel keeps some zones off and arms the others. The contacts stay armed, and the motion sensor in the living room where the animal roams is disabled. If you leave the animal in a particular room, you switch off only that room's sensor, and the rest of the house is fully protected. On many panels, this setting comes as a home or night mode selected with one button.
If contacts are not enough in a living room with large windows, a glass-break detector can be added. This detector listens to sound and is not affected by the animal's movement.
Curtain sensors and outdoor options
A curtain sensor watches a thin plane instead of a wide cone. It is mounted on the inside of a window or balcony door, covering the front of the glass like a curtain. When the animal roams in the middle of the room, it does not enter the sensor's plane. When someone opens the glass and steps in, they cut the plane and the alarm sounds. It helps on sliding doors where contacts are hard to fit and on multi-panel windows.
Owners of detached houses who keep a dog in the garden need to be careful when they want an outdoor sensor. Dogs and cats roaming outside and branches swaying in the wind are the most frequent causes of false alarms for outdoor sensors. If there are animals in the garden, monitoring the outdoor area with a camera instead of an alarm, and leaving the alarm to the doors and windows of the building, usually causes less trouble.
Whichever option you go with, tell the installer where the animal sleeps at night and which rooms it enters during the day. The plan is drawn up according to this information.
How is the test done after installation?
After the sensors are installed, put the panel in test mode. In this mode, the siren does not sound when a sensor is triggered; only a light comes on or the zone name appears on the keypad. Let your pet roam freely in the room, fill its food bowl, toss its toy, and watch for a few days whether the sensor reacts.
Then walk through the room yourself, slowly and bending down. If the sensor does not detect you, the sensitivity is set too low. The aim is not to miss a person while ignoring the animal. Finding this balance on installation day is better than dealing with false alarms for months. Desa Bilişim does this test together with the homeowner during installations and, if needed, changes the sensor's position.
Frequently asked
Can I install a motion-sensor alarm when I have a cat?
You can, but since cats climb high, a pet-immune sensor alone may not be enough. Protecting doors and windows with contacts and switching off the motion sensor in the rooms where the cat roams using partial arming is the method that causes the least trouble.
Does a pet-immune sensor work for large dogs?
A sensor can detect dogs above the weight limit stated by the manufacturer as a person. In that case, no motion sensor is used in the area where the dog stays, and protection is left to the door and window contacts.
Can I replace my existing sensors with pet-immune models?
In most cases, yes. On a wired system, the same cable is connected to the new sensor; on a wireless system, the new sensor must be compatible with the panel. A walk test should be done after the change.
An alarm plan that suits your pet
Tell us about your home and your pet in the quote wizard, and we will prepare a written quote showing where the sensors will be placed.
