Home > Industry Information > Explore The Differences Between Motion Sensors And Infrared Sensors
A motion sensor is an electronic device capable of detecting the movement changes near surrounding objects and is also known as a motion detector.
Broadly speaking, motion sensors can be divided into two major categories: passive motion sensors, which are used to detect environmental changes;
And active motion sensors. For example, ultrasonic sensors emit ultrasonic waves, and when the ultrasonic waves strike an object, they bounce back onto the sensor.
The working principle of a motion sensor is to capture minute changes in the environment. When it detects temperature changes, vibrations or radiation in the environment,
it will send an alarm/signal to your security system or other connected devices (such as lighting equipment).
The motion sensor only supplies power to the lights in a certain area when necessary, which helps save energy. For example, a motion sensor can be connected to a brightly lit area.
In this way, when someone enters, the lights will automatically turn on, and when no one has been active in the space for a period of time, the lights will automatically turn off.
Motion detection: Motion sensors identify physical motion within a given space. A variety of technologies such as microwave, ultrasonic waves and infrared rays can all be used to achieve this goal.
Trigger action: The motion sensor can trigger an alarm, turn on the lights, issue an alarm or activate the camera based on the movement.
Security enhancement: Motion sensors in the security system can identify unnecessary movements, which helps prevent intrusions and warn homeowners or security personnel of possible intruders.
Energy efficiency: By adjusting the on and off of lights and other electrical equipment according to movement, motion sensors can reduce wasted electricity usage, thereby helping to save energy.
Automation: Motion sensors are used in smart buildings and residences to automate various tasks. For example, they can adjust the HVAC system according to the number of rooms checked in.
Applications in different environments: Motion sensors are used to enhance convenience, safety and security in various environments, including public areas, workplaces, residential buildings and industrial sites.
An infrared sensor is a device that detects infrared radiation based on the temperature changes produced by an object. Infrared sensors are widely used in remote controls,
motion detectors and temperature measurement devices. They detect and measure the thermal properties of objects by sensing changes in infrared radiation.
Infrared radiation detection: All objects emit a certain amount of infrared radiation based on their temperature, and infrared radiation sensors can detect this radiation.
Temperature measurement: As the temperature of an object is directly proportional to the amount of infrared radiation it emits, infrared sensors are typically used for
non-direct contact temperature measurement, which is known as non-contact temperature measurement.
Motion detection: Infrared sensors, especially passive infrared (PIR) sensors, can detect motion. Warm objects such as the human body and animals emit infrared radiation,
which is detected by sensors. It utilizes the changes in the movement of objects for detection.
Distance measurement: Some infrared sensors calculate the distance to the target by using the reflection of infrared light. The sensor determines the distance to the object by
irradiating the target area with an infrared beam and calculating the time it takes for the beam to return.
Sensing technology: Motion sensors employ a variety of technologies to identify motion, some of which are as follows:
Passive Infrared (PIR) : Passive infrared (PIR) sensors can detect the infrared radiation or heat emitted by objects. When a warm object moves within
the detection range of the sensor, the radiation changes and a warning is issued.
Ultrasonic waves: These sensors generate high-frequency sound waves similar to those emitted by bats. If the movement causes the sound waves
to produce different echoes, the sensor will detect the movement.
Microwave: The radiation emitted by these sensors is microwaves. They can capture the changes in reflected waves when an object moves, just like ultrasonic sensors.
Signal processing: The sensor processes the detected signals (changes in sound waves, microwave reflections or thermal radiation).
Trigger operation: If movement is detected, the sensor will initiate the pre-programmed operation. This may include:
Alert the security system: The motion sensor in the security application may issue an alert, send a message to your phone or turn on the camera to capture the event.
Turning on the lights: When someone enters the room, the motion sensor can automatically turn on the lights, thereby enhancing convenience and reducing energy consumption.
Controlling smart home devices: Motion sensors can be used in smart homes to activate various functions, such as turning on the thermostat when someone enters the room.
Infrared sensors detect infrared radiation, which is detected in the form of heat.
Active infrared sensor:
The active infrared sensor consists of an infrared light source (LED) and a detector. The sensor emits an infrared beam. When there is an object blocking,
the sensor will sense the change and take appropriate measures.
Passive infrared sensor:
PIR sensors detect infrared radiation produced by warm objects. They do not generate radiation themselves but rather detect changes in infrared energy in the surrounding environment.
(I) Overview
Passive infrared sensors, also known as PIR sensors or passive infrared detectors, are a common type of motion sensor and are frequently used in various applications,
including home security systems and energy-saving lighting.
The PIR sensor is designed with two or three pyroelectric sensors that are sensitive to infrared radiation. These sensors usually adopt symmetrical mirror configurations.
When there is no movement, the two sensors receive the same amount of infrared radiation from the environmental background, and their electrical outputs are balanced.
When a warm object such as a person or a pet moves within the field of view of a sensor, it will enter the area of a pyroelectric sensor before another sensor.
This kind of movement will cause each sensor to receive different amounts of infrared radiation, thereby resulting in an imbalance.
The variation of infrared radiation can cause one sensor to generate a higher electrical output than another.
The electronic circuit of the PIR sensor handles this difference and generates digital output, usually voltage pulses. Then, the digital output is sent to the device or system connected to the PIR sensor, such as a light alarm or security system.
The PIR sensor has a wide field of view, which is attributed to the lens covering the sensor. This kind of lens is usually made of plastic and can focus and bend infrared energy, similar to how a lens focuses visible light. In this way, the PIR sensor
It can detect infrared radiation with a wider coverage.
Motion sensors are widely used in various fields, including:
Safety system: The motion sensor is a key component of the safety system, capable of detecting illegal movement and sending alerts or alarm notifications.
Automatic lighting: The automatic lighting system uses motion sensors to turn the lights on and off based on occupancy, enhancing convenience and energy economy.
Smart home devices: Motion sensors play a significant role in smart home devices, enabling functions such as automatic door opening, heat management, and monitoring.
Industrial automation: Industrial automation uses motion sensors to monitor equipment, detect abnormal situations and maintain worker safety.
Infrared sensors have a variety of uses
Remote control: Due to the wide use of infrared sensors in the remote controls of air conditioners, televisions and other electronic devices, wireless operation has become possible.
Security system: To detect movement and enable the camera and motion detector to achieve night vision functionality, the security system uses infrared sensors.
Temperature measurement: Infrared sensors are used in non-contact thermometers and thermal imagers for remote temperature measurement, which is of great significance in industrial and medical applications.
Industrial automation: To monitor machinery, identify abnormal situations and ensure the safety of workers, industrial automation uses infrared sensors.
Medical equipment: Monitors various physiological factors and uses infrared sensors to measure body temperature.
When it comes to motion sensors, people first think of motion sensor surveillance cameras or motion sensing alarm scenarios.
Motion sensors are good helpers for detecting thieves, thefts and potential threats. Motion sensor cameras and alarms are among the most
needed security systems in commercial buildings, and they can be seen in almost every large building. Nowadays, installing cameras and alarms at home can greatly enhance the security level of the household.
With the help of motion sensors, the lights and cameras will only be activated when motion is detected, which can save a lot of energy and electricity bills.
Lighting waste is one of the major energy wastes in the world. According to data from the US Environmental Protection Agency, by using automatic shut-off
and timed shut-off (such as occupancy sensors (moving sensor light switches)), the energy-saving effect in classrooms can reach 40% to 46%, and that in
private offices can reach 13% to 50%. The energy-saving effect of the restroom can reach 30% to 90%, that of the meeting room can reach 22% to 65%, that of the corridor can reach 30% to 80%, and that of the storage area can reach 45% to 80%.
According to data from Lawrence Berkeley National Laboratory, occupancy rance-based strategies can save an average of 24% of lighting energy consumption.
In residential and commercial applications, occupancy and vacancy sensors can save an average of 30% to 60% of lighting energy, and some can even save up to 80% of energy.
Motion sensors and infrared sensors are two different types of sensors, which respectively detect motion and infrared radiation. Motion sensors detect the motion state of objects,
while infrared sensors detect infrared radiation, such as human body heat. Therefore, there are significant differences between them in application scenarios and detection principles.
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