What is motion sensor and how it works?

A motion sensor is a device that detects movements in areas where it is located. Moving objects within the sensor’s field of vision are detected by the technological structure of the sensor and the sensor activates the necessary alarm systems. Generally used for theft protection.

The motion sensor (or motion detector) is the connection point of our security systems, for example the main device that detects whether someone is in your home when you are not at home. The motion sensor uses one or more technologies to detect motion in a region. If the sensor is activated, a signal is sent to the control panel connected to the monitoring center of your security system, alerting you and the monitoring center to a possible threat in your home.

The following guide will answer all your questions about the different types of motion sensors, the correct placement and how to use them

The role of motion sensor in home security

How motion sensor works
How motion sensor works

The main purpose of motion sensors is to detect an intruder and send a warning signal to your control center. The sensors work when you are at home or when you tell the system that you are not there. When motion is detected, some security systems have a programmable structure to record events with a security camera.

Motion sensors are ready to react to various situations such as movements in your living room or any part of the house, opening and closing windows or doors, or a broken window.

Here are the things that motion sensors can do:

  • Alerts you when one of the young people at home has a curfew
  • When someone approaches the door they can trigger the bell without having to press the bell
  • Children basement, medicine cabinet and so on. alerts you when entering restricted areas in the home
  • Motion sensor can be used to illuminate and save energy in empty spaces
  • Alerts you when your pets are in areas where they should not be.

Motion sensor types

What is pir sensor (PIR):
infrared motion sensor
infrared motion sensor

Detects body temperature (infrared energy). Passive infrared sensors are the most widely used motion sensors in home security systems. When your system is activated, your motion sensors are activated.

When the sensor heats up, it creates a protective grid by sensing heat and movement in the surrounding area. If a moving object obstructs too many grid zones and the infrared energy levels change rapidly, the sensors are activated.

MicroWave (MW) (Radar sensor):
microwawe motion sensor
microwawe (radar) sensor

The sensor sends microwave pulses and measures the reflection of an object that reflects these pulses. They cover a wider area than infrared sensors, but are sensitive to electrical interference and are more expensive.

For this reason, passive infrared sensors are preferred over radar sensors when simple home security and energy savings are at stake.

Dual Technology motion sensors:
Dual Technology motion sensor
Dual Technology motion sensor

Motion sensors can have combined features to reduce false alarms. For example, a passive infrared (PIR) sensor can be combined with a microwave sensor. Dual technology motion sensors are not as likely as other types to cause false alarms, since each sensor is in different areas of the spectrum and one is passive and one is active, because both sensors must be activated at the same time to trigger the alarm. However, this does not mean that it never causes false alarms.

Field Reflector Type:

An LED emits infrared rays on the sensor. Using the reflection of these rays, the sensor measures the distance to the person or object and determines whether the object is within the specified area.


The sensor transmits ultrasonic vibration waves and measures the reflection of a moving object.


Detects vibration. They can be purchased or made easily at home. A homemade vibration sensor activates the switch with the mass on a lever during vibration. Homemade motion sensors can work, but they can also be unreliable.

Other Motion Sensor Features

Wireless motion sensors:

Nowadays, most motion sensors are wireless. You dont need to drill etc. in the assembly process. such as does not require long efforts. Other security systems communicate wirelessly with their components.

Contact Motion Sensors (door / window):
door and window motion sensor
door and window motion sensor

Most contact motion sensors are passive infrared sensors.

When the system is armed, it triggers the alarm when the protected door or window is opened.

Source: https://www.safewise.com/resources/motion-sensor-guide/

Leave a Reply

Your email address will not be published. Required fields are marked *