Motion sensors are used to keep us safe. They are used in security systems to detect, and alarm us when an animal or human has breached the perimeter of the yard or building, thus, allowing for time to respond to the impending attack. This article explains the various types of motion sensors.

Before we begin explaining the motion sensor types, let us first define the term motion sensor.

Table of Contents

What is a Motion Sensor?

A motion sensor is an electronic device that utilizes a sensor to detect nearby motion. These sensors are a key component of security, home control, energy efficiency, automated lighting control, and other systems.

These sensors use the main principle that when an object comes within their vicinity, they will be able to detect its movement, and send a signal to either turn on/off an actuator or send a notification to the owner of the system.

Types of Motion Sensors

1.      Passive Infrared Sensor (PIR)

This type of motion sensor includes a thin pyroelectric film material that responds to infrared radiation by emitting electricity. This sensor is usually used to activate burglar alarm systems when there is an influx of electricity. These sensors are quite popular because they are economical, use little energy and they last for quite a long time.

2.      Ultrasonic Sensors

This type of motion sensor can be further divided into two. There are passive motion sensors, and these are the ones that pay attention to particular sounds. Such sounds include metal on metal and glass breaking. They are very sensitive, are quite expensive and are quite prone to fake alarms.

The second category is the active motion sensor. This motion sensor type generates and ultrasonic wave and determines whether there is motion or not depending on whether the waves are reflected back to the sensor.

3.      Microwave Sensors

This motion sensor type generates microwave pulses. It proceeds to calculate the reflection of these pulses off of objects in order to assess whether there is motion or not. These sensors are quite sensitive, but they have the disadvantages that they consume a lot of power. As a result, they are frequently designed to cycle on, and off. This is a disadvantage as a burglar can easily avoid detection if he or she knows the cycles that the sensor is using.

4.      Tomographic Sensors

This type of motion sensor generates radio waves. It detect when these waves encounter an obstacle. These devices are usually placed in such a way that the radio wave net covers a large area. They are very expensive and as a result, are commonly used in industrial storage facilities and other applications that need deep security.

5.      Combined Motion Sensors

There are types of motion sensors that do not rely on having one type of independent sensor. Instead, there will be a mix of sensors present. These sensors have the advantage that they greatly reduce false alarms. This key advantage is also a disadvantage as these sensors may easily end up failing to give an alarm when a threat is present.

Some Motion Sensor Features

1.      Wireless Motion Sensors

These types of motion sensors do not need any wires during the installation process. All that is needed is a power cable. These sensors have the advantages that they do not require drilling, and that they communicate with other security system components in a wireless manner.

2.      Contact Motion Sensors

These motion sensor types are used to trigger an alarm or raise a notification when a device such as a door or window is opened whilst the home security system they are connected to is active and armed.

3.      Pet Immune Motion Sensors

Some types of motion sensors can be configured to ignore animals up to a specified height. The alarm system has a sensitivity level that can be adjusted for families with very active animals.

4.      Video Motion Sensors

These are motion sensor types that combine video cameras with advanced signal processing. These may allow features such as starting to record the environment each time motion is detected, and saving those recordings to a hard disk. This is a great advantage as these sensors allow for storage space to be saved

Applications of Motion Sensors

1.      Smart Devices

Various types of motion devices are used in smart devices. These include smartphones, fitness wristbands, smart watches, and various other smart devices.

2.      Navigation

Magnetic sensors detect motion by using the magnetic field of the earth. The results from such devices give more accurate directions than what could be obtained by a GPS system, especially indoors. These systems are mainly used for portable navigation, delivering point of product advertising, as well as providing navigation in dense urban areas.

3.      Gyroscopes

These are devices that measure the rotational speed of a device. These were used for military purposes in the beginning, but are now used in smartphones for higher quality gaming and enhancing the navigating experience.

4.      Accelerometers

These motion sensors sense tilt, acceleration and vibration impact. These are used in fitness trackers to measure the number of steps taken by an individual. Some laptops have accelerometers that are present and lock the heads of a hard drive when the laptop falls. This ensures that the laptop’s hard drive does not get damaged, or, encounters as little damage as possible.

5.      Wireless Doorbells

Various motion sensor types are being used in wireless doorbells. This is more effective as the occupant of the house is notified of the presence of guests before they even start to knock the door or ring the doorbell.

6.      Motion Detector Cameras

These are CCTV like cameras that are used in order to catch criminals. These cameras can be interfaced with an alarm system and send a notification to the owner when an unapproved entry is observed. When these cameras are placed strategically, the boost the security of the premises of the area.


This article gave the definition of a motion sensor. It further went on to give the types of motion sensors as well as where they are applied.

We hope you liked the article.