What is Motion Sensing (PIR motion sensor)?

best motion sensing/detector light

What basically is motion sensing or detection?

As the name itself tells the device or circuit which senses or detects the movement of a living or non-living body. It is a wide and great topic of interest in the field of electronics and artificial Intelligence. It is widely used in gaming industry along with toys, electronic equipments, lights, home security and mobile phone also. The term motion sensing looks very interesting.

The basic principle involved behind motion sensing.

To understand the basic principle of motion sensing, you need to first understand the basic two types of motion sensing.

  • Active ultrasonic or microwave sensor

It uses frequencies above the range of human hearing to sense the motion. The sensor calculates the distance between source and destination by transmitting and receiving frequencies and calculate the approximate distance between transmitter and receiver and thus estimates the change in the distance between the two parties. You can think of a radar system, but at a lower level. Because in radar, much high and precise data is required.

It has the capability to sense the motion of any object, i.e. living or non-living. The only requirement is that the frequency should get reflected from the destination object whose motion detection is required. The best example of microwave sensor is RCWL 0516.

  • PIR (Passive Infrared) based

In the case of PIR sensor, an electronic device called PIR is used which only senses the intensity of infra-red radiations from the body whose motion sensing is the topic of interest. If the living body is closer to the sensor it will get good intensity of infrared radiation from the body and when it is far the intensity of infrared radiation decreases (or no IR radiation received) which is being sensed by the PIR motion sensor.

It will only sense the body which radiates infrared radiation (like living beings, animals, hot surface etc.) It will not sense a body which does not radiate infra-red radiation enough to get it sensed by the sensor used in the device. Thus, this Infrared sensing device is good for DIY projects in your home only and is not suitable for commercial purpose.

Proximity sensor (PIR Sensor)

Advantages of motion sensing/ motion detector

  • It can be used to detect a potential intruder near or inside your home or business.
  • Can be used to give alerts if people enter restricted areas.
  • Save energy by powering lights in an area only when required.
  • At home, It can be used in the basement or garage.
  • Manual switching is not required.
  • Can be efficiently used in electronic devices, lights, security system, automation industry.
  • It has endless advantages and scope.
  • Less power consumption
  • Small and miniature

Application of PIR motion sensor/detection

  • Drive alarms and security systems
  • Motion detection based lights
  • Presence sensing device
  • Motion sensor cameras, which includes doorbell cameras at home door entrance¬†and¬†floodlight cameras for exteriors.
  • Indoor motion detectors devices
  • Toys and inside electronic devices
  • Small projects related to motion detection
  • Inside the Smartphone
  • Door and window sensors
  • Burglar alarm and fire sensors


Motion sensing is nowadays the backbone of the automation industry. The involvement of new technology and updates will further improve the automation industry and will prove a boon to the human beings. Almost everyone in this world uses these technologies and when you use something you must know the logic behind the system. We can use this in our DIY projects also to automate a switching application or job. It is widely used in industrial applications nowadays.

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