Motion Sensors

A motion sensor (or motion detector) is an electronic device that is designed to detect and measure movement.

There are two types of motion sensors:

  • Active motion sensors
  • Passive motion sensors

Active motion sensors:

Active sensors consist of both the transmitter and the receiver. When an object interrupts or alters the sensor’s field, the sensor measures changes in between the amount of radiation emitted from the transmitter and reflecting back into the receiver.

Ultrasonic Sensor:

The most commonly used active motion detector uses ultrasonic sensing technology. These motion sensors emit sound waves to detect the presence of objects.When an object moves in the sensing area, the sensor looks for a Doppler (frequency) shift in the wave when it returns to the sensor detector, which would indicate that the wave has hit a moving object. It can also calculate the time between transmission and reflection to calculate the distance. It is used in car parkings systems and other similar applications where precise distance is also a vital factor.

Microwave sensors:

Microwave sensors detect motion using microwave radiation. They emit microwave pulses and measure the reflections off of moving objects. Such sensors are used in automatic doors in shopping malls, home security alarm systems and also used for indoor lighting systems.

Passive motion sensors:

Unlike an active motion sensor, a passive motion sensor does not transmit anything. Instead these sensors measure constant reflection in nature. When an object enters into its field of detection, there is an increase of radiation in its environment. The sensor measures the change and detects objects.

PIR Sensor:

The most widely used type of passive motion sensors is the passive infrared (PIR) sensor. The PIR sensor is designed to detect the infrared radiation emitted naturally from the human body. The receiver is contained in a filter that only allows infrared to pass through it. When a person walks into the room, it detects heat emitted from that person and activates the alarm or turns on the light or any application.

Hybrid motion Sensors:

As the name suggests Combined or Hybrid motion sensor is the combination of both active and passive sensors. Because each sensor has some advantages and disadvantages. So it is basically making a system where multiple sensors active or passive works simultaneously to provide better and accurate results.

Having this kind of system ensures proper security and usability. The system should stay up and running even if one sensor fails to trigger in case an event occurs. It is mainly used in safety and security systems, such as burglar alarm systems. The most popular type of dual technology sensors combines a PIR and a microwave sensor. Combined sensors are also useful for alarm systems to reduce the possibility of false alarm triggers.

Best Motion Sensor + Camera Option :

Wyze Cam V2 with Wyze Sense Starter Kit

Features :

  • Motion detection + video surveillance
  • Up to 26 ft. detection range
  • Motion sensor history

Best for Smart Outdoor Light :

Ring Floodlight Camera


  • Equipped with a security camera with a 140-degree field of view
  • Produces 1,800 lumens of intense light when motion is detected
  • Control the floodlight camera’s activity with Amazon Alexa and the Ring mobile app

Best for Pet Owners:

SimpliSafe Motion Sensor


  • Detects motion within a 30 foot radius
  • Designed with flexibility to be installed on a shelf, wall or in a corner
  • Pet-friendly and designed to avoid detecting pets under 50 pounds

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