A Complete Guide to
Motion Sensors: What You Need to Know

You see a shadow go by your window at night, but you have a feeling they're still out there hiding in the dark. You saw them on your outdoor security camera, and they weren't scared away. After all, you don't have a motion sensor to turn on your floodlight, and now it may be too late.

Had you been sleeping, that person could have been right outside your window and you'd never know it! They cased your house and can get around your security in the dark because you don't have a motion sensor to help you.

Today, we'll cover different types of motion sensors you can use in combination with your alarm and lighting systems. These include options like the active sensor, infrared sensor, and PIR sensor.

Keep reading below to learn more about what a motion sensor is, how motion sensors work, and if you need one.

What Is a Motion Sensor?

A motion sensor is a special device that notices movement within a specified range. This range can be around the detector or just in front of it, depending on what you choose. These are usually used to notice any movement around our buildings and to scare off and illuminate whoever is creeping around at night.

Basic motion detectors notice objects in and around 6.5 feet to 70 feet. You can even purchase ones that detect further than that if needed. Types include optical, infrared, and radio wave motion detectors, which each come in handy for different situations. 

Optical Motion Sensors

An optical motion sensor is equipped with a light source that will illuminate a spot of light on something called the surfacer. When this light is reflected back to the lense and photosensors array, it will follow that target as it moves around in the specific field of view.

Infrared Motion Sensors

Infrared sensors can detect differentiation in heat (such as body heat) within the covered area. They detect the heat and turn on the light, security camera, and an alarm when any changes are detected within the spectrum.

Radio Wave Motion Sensors

Radio Wave, or "Radiofrequency", motion sensors will cast out microwave signals to protect a room or building. When tripped, they will also turn on the light, security camera, and alarm if that's the type you have. Your security camera will know the time that your alarm was set off and show you the corresponding images or video.

Where Is a Motion Sensor Used?

Motion sensors are very useful when they operate in conjunction with other devices like security alarms, lights, and security cameras. The most common use, in fact, is to catch trespassers around or within a home. These are also used for commercial properties.

These detectors, when used together with said devices, can successfully catch an unwanted guest before they get close enough to cause harm to the property or people within the property. Not only that, but the photos or videos taken by the security cameras can be used in court.

Motion sensors are also built into several new technologies these days, like automatic doors, certain smartphones, gaming consoles, robotics, and more. Today we'll tell you about their security uses.

Security and Safety Lighting Systems

Motion detectors are used with lights or systems of lights for safety and security reasons. If a person walks by a monitored area the light will automatically turn on right away. Your security camera will catch that person in a photo or video. 

Motion-activated floodlights are the most popular type of light used with a motion sensor. They're used for security as they light up the outdoor area at night. You can have a system that activates all floodlights around your home and garage when only one sensor is tripped.

For safety purposes, these are helpful and convenient when walking outdoors to a destination in the dark, such as the garage, for example. It can save you money on energy as they're only turned on as you're detected. You can turn off the alarm system for these types of uses.

Occupancy Sensors

Occupancy sensors are used indoors to protect you and your family and detect any movement in the home or specified room. The corresponding light will turn on if motion is detected, and it will turn back off when no motion is detected for a certain amount of time. These can save you lots of money each year, and companies are using these for the same purposes as well.

How Do Motion Sensors Work?

There are three main types of motion detectors, each playing a role in different security or safety situations. These three categories are active, passive infrared (PIR), and combined.

How do motion sensors work and what are the differences between the different types? How could each of these types benefit you?

Active Sensor

These sensors have a mechanism that sends waves or signals across an area such as a room, etc. When the monitor senses a change in the response time of the wave, it is activated. These waves, as we mentioned above, can detect movement and respond extremely fast.

These can even detect branches moving in the wind depending on the sensitivity range set on the detector itself. You'll have to adjust this range if you don't want these small movements to activate your light or lighting system. This is the type of sensor used in shopping malls and other places to activate automatic doors. 

PIR Sensor

A Passive Infrared sensor, also commonly known as a PIR sensor, is used to sense and detect motion. PIR motion detection lights will turn on whether the person or moving object is inside or outside of the range. These are less expensive than active sensors, are easy to operate, and use less power than active sensors.

These are commonly built into gadgets and appliances in businesses or homes. They're also known as "IR motion" or "Pyroelectric" sensors.

Combined Sensor

Also known as "Dual Technology" sensors, these will use multiple types of motion sensing technology at once in order to reduce false alarms. Both types of sensors would need to be tripped in order for the alarm or light to be activated. This narrows down the source, but they aren't always perfect, so you may get a few false alarms along the way.

Less Common Types

These motion detectors are less commonly used, but are still worth discussing:

• Ultrasonic motion sensors reflect pulses of special ultrasonic waves off of moving objects
• Vibration motion sensors work by sensing even the smallest vibration in a room; you can make these yourself, however, homemade vibration detectors are unreliable

It's best to stick with what is popular and proven to work reliably and consistently when your safety and security are on the line.

Why Do I Need Motion Sensors?

Your entire property should have motion sensor coverage so whoever or whatever is out there is promptly frightened away by the activation of your floodlights. If you have a large yard, they can be set up far away from your building so that the authorities are notified before they get to your door or window.

Lights that are high-powered and on all night will take a lot of power and result in huge electricity bills for you and your family. But normal floodlights are constantly on will create a lot of lumens, which means they're very bright and energy-consuming. These could bother your neighbors at night if continuously on.

Outdoor motion sensor lights only come on when tripped.  By using a motion sensor with your floodlights, you're only paying for the lumens you need to use, in an emergency situation or when you choose to use them. 

With solar-powered lights, you don't have enough lumens to scare someone away. Plus they're not going to work all night. To solve your problem, you'll need something called a motion detector or motion sensor. This device will work in conjunction with your light fixture.

Stay Safe With High-Quality Motion Sensors

Now you know the answer to, "How do motion detectors work?" So, give yourself and your family peace of mind with the right one. Whether you choose a PIR sensor or an infrared sensor, or another type altogether, you can rest assured ADT will help scare off unwanted intruders. 

Motion sensor security technologies have come a long way over the years and continue to be improved exponentially. Keep your home or business safe this year and into the future with new ADT home security sensors today.

Wondering if a home security system is right for you? Contact us today for a free quote!