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How Do Motion Sensors Work?

On February 21, 2022, In Uncategorized,

Home security is important, especially since in 2019, there were estimated to be over one million burglaries. Motion sensors are ideal to add to your home to improve security, but few people truly understand how they work.

Here are some of the details you need to know about motion sensors to help you pick the best option for updating your home’s security system.

What Is a Motion Sensor?

Motion sensors, or motion detectors, can be used for various purposes when it comes to your home security needs, but in general, they are activated when they sense motion. You may have heard or seen motion-activated lighting because it’s quite common for home security use and practicality purposes.

For example, a light might be activated by a burglar, which may scare them away. These kinds of motion sensors are particularly helpful if you have a lot of property where someone might hide. Motion sensors can also be connected with the lights in a room so that the lights automatically turn on when someone enters and turn off after a period of inactivity in the space.

More broadly, there are passive motion sensors and active motion sensors. Passive motion sensors detect variations in light or heat, while active motion sensors send out ultrasonic waves that come back to the sensor.

motion sensor mounted on wall

In general, motion sensors are used to detect an intruder on your property, which then alerts a control panel. After that, your monitoring center would be alerted. The sensors are activated whenever you arm your system.

Motion sensors protect you by guarding your home in different situations. Here are a few ways you might be able to use your motion detectors:


  • As an alert, if your teenager breaks curfew
  • To trigger your doorbell when a person comes up to your door
  • To automatically off the lights when someone has left a room
  • As an alert for when your pets enter restricted areas in your home

Motion sensor camera systems are also activated by motion. You can use them in tandem with motion sensor lighting so that your camera has some light to work with when capturing the source of motion.

You can also use motion sensor camera systems for perimeter fences, especially if you have a large amount of land to look after. You can place these camera systems around the perimeter of your land, and you’ll be alerted if they are triggered.


Types of Motion Sensors

There are three common types of motion sensors that we will look at in detail to determine how they keep you and your home safe.

Passive Infrared Motion Sensors

Passive infrared motion sensors are often used in restrooms or office spaces, and they usually have a white cover. They are typically inexpensive, small, easy to use and require low power. This type of motion sensor gets triggered by sensing a change in temperature between a warm body and the background.

More specifically, passive infrared sensors are able to detect infrared radiation. The sensors have two slots made out of material that is sensitive to this type of radiation. Ultimately, this kind of sensor gets triggered when there is a differential change between the two slots.

Microwave Sensors

Microwave sensors detect motion through the use of continuous waves of microwave radiation. This type of sensor will emit high radio frequency and then looks for a frequency shift to measure the reflection off of an object. If there is a frequency shift, the microwave sensor gets triggered.

Overall, you can use microwave sensors to cover larger areas than passive infrared sensors. However, they tend to be more expensive and can cause more false alarms because they’re able to “see” through walls.

Dual-Tech Sensors

Dual-tech sensors use both microwave sensors and passive infrared sensors so that you end up with fewer false alarms. If there is a fast increase in temperature, the passive infrared sensor will get triggered and then will activate the microwave sensor. Because both sensors have to be triggered, there is less likelihood of there being a false alarm.

Best Places to Put Motion Sensors in the Home

The best places to put motion sensors depend on what kind you are using. For example, if you’re using a contact sensor, it’s best to put it on a door or a window — when the door or window opens, a magnet and the sensor move apart, which triggers the alarm.

In general, it’s best to place sensors 10-15 feet away from sunny windows, heating vents and radiators. This is because a quick change in heat can trigger a false alarm. It’s also a good idea to place any motion sensor in areas that must be walked through to get around your house, such as a main hallway or stairwell. Where you place your sensors will depend on the layout of your home, but it’s common for intruders to try and enter the home through garage doors, patio doors and front or back doors.

Another thing to keep in mind when placing your sensors is that most work best when the person walking by is moving parallel to it. Also, the most useful locations to place sensors tend to be in corners, high up and opposite of any main entrances when possible. That way, the sensors, especially infrared, can cover more area.

contact wayne alarm for motion sensors

Contact Wayne Alarm

If you’re wanting to update your home security with a new alarm system or alarm monitoring services, you can count on Wayne Alarm for guaranteed satisfaction. We have been in business for over 50 years, and we know what it takes to get you the service you need. We pride ourselves on giving each of our customers the personalized attention they require to ensure they get the best system for their situation.

To get to know more about us and what we can do for you fill out our online contact form or request a free quote when you call us at 781-595-0000.

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