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What is a Motion Sensor?

Author: Apogeeweb
Date: 9 May 2022
outdoor motion sensor light



Introduction of Motion Sensor

Related Video

Types of Motion Sensors

Ⅰ Active Motion Sensors

Ⅱ Passive Motion Sensors

How Do Smart Motion Sensors Work?

Pros and Cons

A DIY Guide


Introduction of Motion Sensor

A motion sensor or motion detector is an electronic device that uses sensors to detect nearby human beings or objects. Unlike many other types of sensors, motion sensors are typically embedded systems consisting of three main components: a sensor unit, an embedded computer, and hardware (or consisting of mechanical components). When the motion sensor detects a moving object, it will perform data analysis and data comparison in the system, and send an alarm message to your mobile device through the Internet, so that you will know immediately if there is a security problem in the detection area. In addition, if you subscribe to a merchant's monitoring service, you can even set up motion sensors to automatically send alerts to the monitoring team.


Video: Motion Sensors as Fast As Possible

Video Description:

Motion sensors have changed pretty significantly in the last 20 years. We even have sensors that detect their own motion! Wait... how does that work?


Types of Motion Sensors

Active motion sensors and passive motion sensors are two types of motion sensors.


Ⅰ Active Motion Sensors

In a specific region or area, active motion sensors continuously emit energy in the form of infrared light or an electrical field. When people or objects with heat or temperature pass through this area, they cause temperature disturbances that can be detected by the motion sensor.Active motion sensors include both emitter and reflection detection circuits, but they use more energy than passive motion detectors. Active motion detectors are classified into three types: microwave, tomographic, and ultrasonic.


Microwave Sensors

These sensors generate microwave pulses and then calculate their reflection off of objects to determine whether or not the objects are moving. Microwave sensors are extremely sensitive; the frequency at which the waves emitted differs if the waves are reflected by any moving object. However, these can sometimes be seen in nonmetallic objects that can be detected moving objects outside of the target range. Because it consumes a significant amount of power, these sensors are frequently designed to cycle ON and OFF. If you understand the cycles, you can acquire past them. Microwave sensors are used in electronic guard dogs.


Tomographic Sensors

When waves goes wrong, these sensors generate radio waves and detect them. They can see through walls and objects and are frequently embedded in a network of radio waves capable of covering large areas. Because these sensors are expensive, they are commonly used in warehouses, storage units, and other commercial-level security situations. Because these sensors do not require line of sight, they can detect movement in concealed areas up to 5,000 square feet high. When a disturbance in the grid network is detected, the sensor activates the motion sensor alarm.


Ultrasonic Sensors

Ultrasonic sensors can be active (or) passive, with passive ones listening for specific sounds such as metal on metal or glass breaking. These sensors are extremely sensitive, but they are often prohibitively expensive and prone to false alarms. Active ones generate ultrasonic wave (sound wave) pulses and then determine how these waves are reflected off a moving object. Animals such as cats, dogs, and fish can hear these sound waves, so an active ultrasonic alarm could startle them. An ultrasonic detector, in theory, emits high-frequency sound waves that are reflected back to the sensor. If the sound waves are interrupted, the active ultrasonic sensor may sound an alarm.


Ⅱ Passive Motion Sensors

Passive motion sensors are opposite to active sensors in that they do not emit anything but simply detect infrared energy. Passive detectors detect infrared (heat) energy levels. Passive sensors scan the room or area, looking for infrared heat emitted by living beings.


Passive Infrared Sensor (PIR)

The PIR sensor is a pyroelectric sensor that is divided into two halves so that whenever a moving object emits infrared radiation, each half cancels the other half if both halves have the same IR radiation – then the sensors do not sense – but if it finds any more or less IR radiation, the PIR sensor senses. There are various PIR sensors available with varying coverage areas.Because the PIR Motion detector is easily obstructed by the variability of heat sources and sunlight, it is better suited for indoor movement detection within a closed environment.


Dual-technology Motion Sensors

In addition to active and passive sensors, the progress of motion sensor technology has also developed dual-technology sensors, that is, combining different motion sensor technology to develop motion sensors, reducing the false trigger sensor. The early motion sensors discussed in this article can fail in certain situations, such as the PIR sensor that can be incorrectly activated by changes in heat and light without the object actually moving. Similarly, if something causes the sensor to activate motion, the microwave sensor can also be activated incorrectly. Therefore, in order to avoid these disadvantages, we can combine sensors, such as PIR and microwave sensors to improve efficiency. Here, by using two sensors at the same time, even the PIR sensor can be activated by changes in heat or light without involving object motion, but the microwave sensor can't be activated, so the motion sensor switch can't be activated either. Similarly, the motion sensor switch cannot be activated by the combined sensor even if the passive arm of the microwave sensor is activated and the PIR sensor is not.


How Do Smart Motion Sensors Work?

The majority of smart motion sensors employ passive infrared (PIR) technology. PIR sensors detect infrared energy emitted by humans and other animals as body heat. As a result, if the temperature suddenly rises, your device will detect it and notify your system's control panel. PIR sensors can be programmed to ignore minor temperature changes, so you don't have to worry about your pets accidentally setting off alarms.


Motion sensors can be used to turn on a light when someone approaches your home, to sound an alarm when movement is detected in your living room, or to trigger a motion sensor camera to begin recording when someone enters your home.



Pros and Cons

Pros of motion sensor:

The following are the benefits of active and passive motion sensors:

1.It is suitable for use in harsh environments with irregular heat cycles (Active Motion Sensor).

2.It has a longer lifespan of approximately 100000 hours (Active type).

3.It reliably detects motion in both light and dark conditions indoors. (Sensor of Passive Motion)

4.It contributes to security by detecting suspicious movement.

5.Motion sensors are simple to install.


Cons of motion sensor:

The following are the drawbacks of active and passive motion sensors:

1.High-powered radio frequency is hazardous to humans (active type).

2.Microwave radio frequencies do not penetrate metal objects (active type).

3.Passive motion sensors do not work above 350 degrees Celsius.

4.Passive sensors only work in LOS (Line of Sight) areas and do not work in non-LOS areas.

5.The passive type is unaffected by very slow object motion.

6.The Passive Infrared (PIR) Sensor can detect humans within a 10 meter range.

7.The PIR sensor type can be triggered by any moving object.


A DIY Guide

A guide for your DIY sensor system:

If you want to do your own security, make sure to follow the instructions that come with the sensor. Here are some pointers for installing motion detectors in your home or business:


Install sensors near entrances. Motion detectors designed specifically for doors and windows are available.


Set them up in high-traffic areas. Installing the sensor in a hallway, stairwell, or other area where people must pass through increases the likelihood of catching an intruder. It's also a good idea to put sensors in rooms with particularly valuable items, where thieves are likely to go first.


Install PIR sensors away from heat sources. PIR sensors analyze temperature fluctuations in a given area and can cause a false alarm if installed too close to a vent, furnace, or fireplace.


Don't obstruct the sensor. If the sensors are obstructed, they will not function properly. An impediment may not be obvious at first. For example, if you install a motion sensor light above your driveway, your parked car may interfere with its ability to detect motion on the sidewalk or in the street. Install the sensor in an area where there is no obstruction.


Wipe the sensor clean after installation to ensure an unobstructed lens, and remember to clean it on a regular basis after that.



1.Should I have motion sensor lights installed in my home?

Indoor motion detector lights are less common than outdoor motion detector lights, but they do exist. These are typically LED models that are energy-efficient and designed to illuminate garages, workspaces, or dark hallways. They can also be used to install in-home entryways, eliminating the need to fumble around for the light switch when you arrive home at night.


2.What is a smart motion sensor?

Smart motion sensors detect movement in and around your home and initiate an action in response. When a smart motion sensor detects you entering a room, it can automatically turn on the lights. Alternatively, they can send you an alert if an intruder attempts to enter your home. Finally, the goal of motion sensors is to provide peace of mind while also making your home run more smoothly and efficiently.


3.What is a PIR Sensor?

The PIR is a motion sensor with a white cover that you may have seen when entering a restroom or an office space. They are small, low-power, simple to operate, and inexpensive. It detects movement by detecting temperature differences between the background and a warm body.


4.How microwave sensors work?

Microwave sensors detect motion by using continuous waves of microwave radiation, similar to how a radar speed gun works. It sends out a high radio frequency and detects a frequency shift to measure the reflection off an object. If a frequency shift is detected, the motion detector is activated.


5.How do you reset an outdoor motion sensor light?

Turning off and back on for 30 seconds or longer is the best way to reset a motion sensor light. A homeowner can also turn off the power to it at the breaker to give it time to reset itself. If that doesn't work, the sensor or the bulb may be at fault.


6.Can you add a motion sensor to an existing light?

For both residential and commercial lighting, a motion sensor adds safety, security, and convenience. If an existing light is in good working order, adding a light sensor does not necessitate replacing it. Rather, use a motion sensor adapter to convert existing lights to motion sensor lights.


7.How do you adjust a motion sensor switch?

Users can change the settings of the motion sensor light switch by switching toggles under the cover or pressing buttons on the surface. Auxiliary buttons or toggles behind the cover plate are used to program many of the classic motion sensor light switches.


8.How to fix a motion sensor light?

Turning off and back on for 30 seconds or longer is the best way to reset a motion sensor light.


9.Why is motion sensor lighting a good investment?

Installing a motion detector light is a simple task that is well suited to the homeowner who is willing to put a few minutes into improving their home. The task depicted in the photos here, showing the replacement of a defective light, took only about 15 minutes and no special tools.


10.Where are motion sensors used?

A motion sensor (or motion detector) is a type of electronic device that detects and measures movement. Motion sensors are most commonly found in home and business security systems, but they are also found in phones, paper towel dispensers, game consoles, and virtual reality systems.


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