Your Guide to Motion Sensors and How They Enhance Your Security

Woman activating settings for her home's motion sensors

A high-quality security system keeps you, your family, and your possessions safe while inside your home. Among the features of your security system, you’ll probably need one or more motion sensors. When a motion sensor detects movement, it sends a signal to your security system’s control panel to alert you of potential danger inside your home.

Whether you’re seeking a security upgrade or are looking for your first security system, learning about motion sensors can help. This guide will provide information about the types of motion sensors available, the job of motion sensors in your security system, and how to choose the best motion sensor for your security needs.

This ultimate guide will teach you more about:

What Is a Motion Sensor?

A motion sensor is a device that detects and reacts to movement. This means that motion sensors are used fairly commonly in everyday life. For instance, automatic faucets contain a sensor that detects movement beneath the faucet. Many people have floodlights or pathway lighting that turns on when you enter the driveway or near the lights.

Motion sensors also used in a security system might send a signal to the security control panel to:

  • Sound a loud alarm
  • Turn on lights
  • Even automatically call the police

Other security solutions that include motion sensors within equipment might mean that a home is equipped with motion sensor lights or a camera that begins recording when motion is detected. There are a variety of types of motion sensors used in security equipment designed to protect your home.

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Types of Motion Sensors

While all motion sensors detect movement, they can work in different ways and produce various reactions as a response. The type of motion sensor(s) you choose will depend on your unique situation and your complete security system.

For example, some types of motion sensors help you avoid false alarms that can be triggered by pets; others are designed to detect movement for a wide distance. Motion sensors in security systems use different types of technology to detect movement and produce the expected response. These are the most common motion sensors used in security systems.

Passive infrared sensors

Passive infrared (PIR) sensors work by detecting temperature change emitted by body heat. They remain dormant until a person or animal moves into the sensor’s detection range, then alert you when a designated temperature change occurs. Since heat is constantly emitted by all surfaces, PIR sensors are set to detect sudden changes within a given area. They can also be programmed to handle small changes, so you can use your alarm at night without accidentally triggering it or your pet can move about freely while you’re not home.

Dual technology sensors

Some motion sensors use multiple technologies to avoid false alarms. This could mean a combination of PIR and microwave technologies are used within the same sensor. Usually, the technologies working in a dual sensor are opposite (one is active and one is passive). To activate a dual technology sensor, both types of sensors must be triggered to send an alarm. Since the sensors work differently, false alarms tend to occur less frequently.

Microwave sensors

These sensors detect motion with the use of safe electromagnetic radiation to emit waves that are reflected back to the sensor. Microwave sensors constantly send out pulses and measure reflections off moving objects. When a new object (like an intruder) enters the sensor’s field, the change is detected. Microwave sensors generally work over a larger area. But they can be extremely sensitive and possibly triggered by electrical interference.

Ultrasonic sensors

Unlike passive infrared sensors, ultrasonic sensors are continually active. They emit sounds at a frequency above the range of human hearing. The sound waves bounce off objects in the area and return them to the motion sensor. Simply put, ultrasonic sensors continually send out inaudible sound waves and determine the closeness of objects in the area by echoes that return to the base. When new objects enter the field, an alarm is triggered. These sensors can be configured to a specific sensitivity level to avoid triggering an alarm for objects beyond a certain distance.

Photo sensor detectors

Sometimes used on cameras, photo sensor detectors use light to detect motion. For example, a motion-detecting camera on your front porch will begin recording when someone passes between the sensor and the light source. Blocking the focused beam of light creates a shadow that triggers recording.

Tomographic sensors

While these sensors evoke the movie image of alarm systems, they are used less frequently as technology evolves. Tomographic sensors use a webbed or grid network of radio waves that trigger an alert when the link between two nodes is broken.

Vibration sensors

Like the name implies, vibration sensors detect small vibrations that movements make as people enter a room. This can include footsteps or other movements as items shift around. These sensors are used less frequently and can be less reliable than other motion sensors.

How Your Motion Sensor Works

Your motion sensor detects movement within a certain range, but that’s not the only job it does. Motion sensors can trigger:

  • A camera to begin recording
  • Lights to come on inside or outside your home
  • An alarm that sounds immediately when a door or window begins to open

When you choose a motion sensor to enhance your home security, the way it activates is an important part of the choice. Like the varied technologies that trigger motion sensors, there are different ways sensors can generate a response. These are some of the most common ways security motion sensors alert you of a potential intruder.

  • Contact sensors: Designed to be installed on doors and windows, contact sensors are activated when a protected window or door begins to open.
  • Video sensors: Some sensors can trigger a camera to begin recording when motion is detected. This can be especially helpful to record and report criminal activity.
  • Pet immune sensors: Some sensors can avoid certain triggers. Pet immune sensors can be calibrated to ignore animals up to a certain weight, allowing your pet to move freely about the house while the alarm system is on.
  • Motion sensor lights: The convenience of lights that are activated by motion in a certain area can extend beyond security. For example, the lights that come on when you enter your driveway provide a safe passage indoors. This technology can also light up a room when you enter. Similarly, motion sensor flood lights outside your home can frighten a criminal away before they enter your home.

Pro tip for choosing the right motion sensors:

Using motion sensors to protect your garage can be a valuable security feature to help keep your stored belongings and vehicles secure.

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Why Motion Sensors Are Important

A motion sensor attached to a wall in a living room

If you’re on the fence about getting motion sensors, it’s a good idea to consider the benefits they provide and if your home needs them. Unfortunately, every unprotected home could be a target for an intruder. Criminals target homes for a variety of reasons in both urban and rural areas.

While there might be bigger, more expensive homes on your block, your home could be more accessible. Also, your yard may offer better coverage from the street or a neighbor’s view.

In addition to your security system, motion sensors provide a variety of benefits, including:

Improved home security

If you’re concerned about the potential for intruders to enter your home, motion sensors can offer a greater sense of security. Maybe you have a security system in place and a camera located near your front door. The addition of motion sensor floodlights could provide even more security by keeping potential intruders from getting close to your home and seeking ways to get past your security system. You can place motion sensors for home security around doors, windows, and your garage to alert you to an unwanted presence in a variety of ways.


Motion sensor lights aren’t only activated by criminals. When you arrive home after dark with a trunk full of groceries or a sleeping toddler in the back seat, floodlights that illuminate the path to your front door make your life a lot easier. Motion sensors can provide the same convenience inside your home by lighting a room after detecting motion or turning on your faucet without the need for you to turn a handle.

Enhanced safety

Besides potential criminals, there are other dangers that could lurk outside your home. More frequently, residents in cities and rural neighborhoods have interactions with wild animals that venture too close to home. Whether you’re taking out the trash, your child is making a quick dash outside to retrieve a forgotten toy, or you have an errand to run, motion-detecting lights can alert you to dangers existing outside your home. In many areas, nightfall in winter comes before the workday is complete. Dependable lighting can help you navigate snow and ice on your pathways and steps or avoid unexpected obstacles that could cause serious injury.

Energy savings

Motion sensors eliminate the need to leave your outdoor lights on for extended periods of time. For many large families with a variety of evening activities, outdoor lights must stay on for hours until everyone is safely home. Even worse, some homeowners simply prefer to leave lights on for the entire night to improve security. This can quickly drive up your energy bill. Motion sensor lights can significantly reduce those costs and help you avoid potential arguments with your neighbors.

Enhanced protection for your family and pets

Motion sensors can go near exterior doors to alert you to an intruder entering your home. The same sensors can do double duty when your curious child ventures outdoors when you’re loading the washer or otherwise occupied. Motion sensors can even go inside your home to provide additional control. For instance, a motion sensor at the top of a stairwell could prevent a slip and fall injury, or a sensor placed near specific doors can keep your puppy corralled to a safe zone within your home.

Things to Consider When Choosing a Motion Sensor

Your motion sensor has an important role to play in protecting your home. That means choosing the right motion sensor or combination of motion sensors will be a job you need to take seriously. Every home is different, and choosing motion sensors that suit your home and unique lifestyle will mean they’re used more frequently. Consider these things when choosing motion sensors for your security system.

Wired vs. wireless

Hardwired security systems rely on a hardwired system to receive power and transmit signals. A professional generally needs to install these systems. Wireless systems use a secure network to keep your devices connected. Both systems depend on motion sensors for accurate detection of unwanted entries to the home. But each has distinct differences.



  • Always have power except during a power outage
  • Have fewer working parts
  • Don’t depend on internet service
  • Less likely to experience electrical interference


  • Generally require professional installation
  • May limit the number of cameras you can install
  • Often requires home repair after installation
  • You cannot easily move hardware



  • Easy installation that homeowners can often complete without professional assistance
  • Integration with smart home devices
  • Easy to upgrade
  • Battery operation
  • Remote access for a variety of tasks


  • It can be unreliable if you have spotty Wi-Fi.
  • Cameras and other hardware can be vulnerable to hacking.
  • More interference is likely.

Pets in the home

If you have pets, keeping motion sensors on while you’re at work can be a hassle. You need your home and your pet to be safe, but fielding false alarms all day can seriously impact your performance at work. Luckily, solutions are available that allow your pet to roam freely and still keep out intruders. You can calibrate some PIR sensors to ignore animals up to a certain weight, but they’ll still send out an alert if a person (heavier than your pets) enters the home. Some of these sensors are even sensitive enough for you to adjust to your family’s lifestyle.

Video capability

Many homeowners choose to install an alarm system that focuses on using lights or noise to simultaneously frighten potential intruders and alert you to a threat. But there are additional benefits of a video sensor you don’t want to overlook. Video sensors begin recording when movement occurs within a certain area. This can provide extra security and convenience to your home. Consider these benefits to determine whether video sensors are right for your home.

  • Footage can help identify a criminal or provide proof for law enforcement.
  • Video sensors can act as a doorbell or alert you when packages arrive.
  • Video sensors can act as an alert when your teen doesn’t arrive home on time.

Your sensor’s visibility

When criminals seek homes with easy access, they avoid homes with evidence of a security system. Adding features that will be easily noticeable can act as a deterrent for would-be intruders. For instance, motion-detecting lights quickly draw attention. Cameras located near the front entryway are typically easy to see, as well.

How your motion sensor works to alert you of activity

Motion sensors work in a variety of ways, and the type you use will depend on your lifestyle. Consider these questions as you explore the different types of motion sensors available.

  • Do you need security for windows and your garage, as well as your front door?
  • Can you use the convenience of motion sensor lights outside your home?
  • Do you need a sensor that connects with your mobile device?
  • Will video provide added convenience and simplify your daily life?
  • Can indoor sensors provide added safety features to your home?

Pro tip for choosing the right motion sensors:

Adding a motion sensor to your outdoor shed or other storage building can improve the security of belongings that criminals might otherwise see as an easy target. Check out our guide to the best storage unit locks for more storage security solutions.

How to Install a Motion Sensor

Man installing motion sensors to improve home security

Since most motion sensors are wireless, installation isn’t difficult. With a few common household tools, you can likely take care of the complete installation process without requiring professional assistance. Follow these simple instructions when installing your motion sensor.

1. Inspect the contents of your device

Unbox your motion sensor in a clean area where you can lay out all the components and ensure nothing is missing. Read through the instructions to prepare for the installation process. Take the time to install the required batteries before beginning installation.

2. Choose your location carefully

Putting your motion sensor in an area that will be useful without triggering an abundance of false alarms is a careful balancing act. Try to seek a vantage point that covers a large area without being obscured by household items. These tips can help you find the best location for your motion sensor.

  • Corners offer a wider range of coverage.
  • Tall furniture can limit the passive infrared energy range.
  • Always mount sensors opposite of main entrances to catch the most traffic.
  • Take advantage of hallways and stairwells since traffic must pass through them to access the rest of your home.

3. Mount the sensor

Most motion sensors are very lightweight and can be mounted practically anywhere. If you’re mounting your sensor in a high location, use a safe stepladder and gather any required tools before you begin. Installation will require a screwdriver or electric drill. To mount your sensor, remove the mounting bracket from the main body. Screw the mounting bracket to the wall, then click the sensor into place.

4. Connect the sensor to your system

Follow your manufacturer’s instructions to connect your new motion sensor to your alarm system. If connecting additional smart home devices to the motion detector, complete this step last as directed in the instructions.

5. Adjust the settings

Many motion sensors are designed with a variety of settings to meet different needs. Examine the settings for your device and set them in the way that best works for your home. The settings may include pet sensitivity, delayed alarm, and mobile device alerts.

Additional installation tips for success

Installing your wireless motion sensor is a fairly easy job. However, there are things that can inhibit the range of your motion sensor or cause an increase in false alarms. Learning more about the way these sensors work can help you avoid these issues. Use these tips to help eliminate common installation issues.

  • Outdoor overhangs like carports can reduce the range of your sensor.
  • Placing pet-sensitive motion sensors near stairwells can lead to false alarms.
  • Avoid placing sensors near a heat source.
  • Consider potential obstructions that might not be in place during installation (like your car or an empty coat rack that will be full in the winter).
  • Install sensors near entry points for the earliest alert
  • Create a schedule for changing batteries on time, and always ensure your batteries are ready to use with proper battery storage.
  • Clean your motion sensor every month to avoid interference from dust buildup.
  • Avoid placing video-enabled sensors where they’ll detect the movement of street traffic.
  • When placing an infrared sensor, use a light to detect range. The shadowed areas could represent spaces where the signal will be blocked.
  • Consider your pet’s activities when using a pet-sensitive motion sensor. High jumping dogs can trigger false alarms since they look larger to the sensor.
  • Add motion-sensor lights in areas that will provide added convenience to your family.
  • Avoid drafty and sunlit areas when installing an infrared sensor.
  • Consider the benefits of using multiple types of sensors for a complete security solution.
  • Place a sensor near the master bedroom since it’s the area many criminals search for valuables.
  • Consider all the things that can set off different types of sensors, including dust, bugs, passing traffic, animal activity, temperature changes, sound, and low batteries.

Final Thoughts on Motion Sensors

Different types of motion sensors provide you with a variety of ways to add security and convenience to your home. Adding a motion sensor or additional motion-detecting lights to your garage or outdoor shed can also help you protect your home’s storage space. After learning about the capabilities of motion sensors, it’s easy to understand why they’re considered by many to be the backbone of any good security system.

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