Wholesale Capacity Touch Motion Sensor Switch

You must have seen automatic sensing hand dryer and water tap in a public toilet but do you know how do they work? It is the motion sensor that makes people achieve the new world of automation. There is a variety of motion sensors on the market, but all fall into one of two categories: active motion sensors (active sensors) and passive motion sensors (passive sensors).

The first motion sensor

In 1950, Samuel Bango invented the first motion sensor, which is a burglar alarm. Samuel applied the basics of radar to ultrasound whose frequency has the ability to detect a fire or a robber and cannot hear by humans. And this is why motion sensors can work as a burglar alarm.

Motion sensors powered by electricity are designed to detect and measure motion. Motion sensors are mainly used in home and corporate security systems, but can also be found in phones, paper towel dispensers, game consoles, and virtual reality systems.

Types of motion sensors

As we mentioned above, active sensors and passive sensors are the main two kinds of motion sensors. Active motion sensors are also known as radar-based motion sensors. It has both a transmitter and a receiver and detects movement and it detects movements by measuring changes in the amount of sound or radiation reflected back to the receiver.

Active motion sensors

An active motion sensor emits radio waves/microwaves that look for doppler (frequency) changes in the wave as the object moves in the area covered by the motion sensor. When the changing wave returns to the sensor detector, this will indicate that the wave has reached the moving object. Motion sensors can receive these changes and send electrical signals to alarm systems, floodlights, or other types of devices connected to motion sensors.

Active motion sensors are commonly used in automatic (china oem)door switches in large shopping malls, also in house security alarm systems, and used in indoor lighting systems such as auto freezer lights.

The most common active motion sensor is the ultrasonic motion sensor. Ultrasonic motion sensors emit sound waves to detect the presence of objects. There are also microwave motion sensors (which emit microwave radiation) and tomography motion sensors (which send and receive radio waves).

Passive motion sensors

Passive motion sensors are different from active sensors since they have no emitter and they emit nothing but detect infrared energy. The most popular type of passive motion sensor is the passive infrared (PIR) sensor.

PIR sensors

Passive infrared sensor has applied the principle of thermal radiation as the way it detects movements is by sensing the temperature gap between the environment and the warm body. All objects with a temperature above absolute zero produce thermal radiation, and the higher the temperature, the greater the total amount of energy radiated so the range of the application of PIR sensors is broad.

PIR sensors consist of pyroelectric thin film materials that emit electrical energy in response to IR radiation. The PIR has two slots made of special materials that are sensitive to infrared. When the sensor senses a change in the difference between the two slots, this causes a pulse that the sensor detects as "motion. Passive infrared sensors features in its small size and cheap price, as well as low power consumption, so they are widely used in indoor alarms, automatic sensing of toilet sinks, etc.

Ultrasonic sensor

Active ultrasonic motion sensors generate ultrasonic pulses (sound waves) and then receive the reflection of those waves off a moving object. Cats, dogs, fish and other animals can hear these sound waves, so an active ultrasonic alarm may upset them. So if you have fed a pet, you had better not choose active ultrasonic motion sensors for your home.

In addition, ultrasonic motion sensors can be active (active) or passive (passive). Passive ultrasonic motion sensors are too sensitive to sensor the special sounds such as metal and broken glass, so they are prone to give false alarms while passive ultrasonic motion sensors are usually expensive.

Microwave sensors

Microwave motion sensors detect motion by emitting a continuous stream of microwave radiation, similar to the work principle of radar speed indicator.

Microwave sensors are very sensitive and can sometimes sensor non-metallic objects and detect moving objects outside the target range. They cover a larger area than PIR sensors, but more expensive and susceptible to electricity interference. What’s more their ability of penetrating materials usually causes false alarms. Microwave sensors also consume more power, so they are often designed with open and close mode. The most common application of microwave sensors is the electronic police dog.

The application of motion sensors

Motion sensors have a wide range of uses which are mainly used in daily life to detect abnormal movements in the home. Today, most smart devices come with built-in motion sensors that have proved essential in the modern era.

Smartphones and wearing electric devices: motion sensors can be used in smartphones and wearing electric devices. In addition to motion sensors, it also includes other sensors such as magnetic sensors, and gyroscopes.


Security : motion sensors also have a wide range of applications in home and personal security. Security systems without motion sensors are impossible to achieve.

Lights with motion sensors switch: even on busy nights, they can provide a clear view and let homeowners know if there are intruders at night. They also save money, as they can turn off the switch automatically when the homeowner forgets to do so.

Mobile sensor alarms, usually integrated with burglar alarms, can send an alarm when an intruder is detected. They are used to scare off thieves.

Motion-detector cameras, like CCTV cameras, are useful in catching thieves.

Motion sensors are also an important part of wireless doorbells, sounding an alarm when guests arrive at the door.

Motion sensors, especially PIR sensors, are widely used in our daily life. If you haven’t a motion sensor in your home, you should have a try to experience an automatic and more freedom life. We are a professional PIR Sensor Switch oem manufacturer. If you are interested in our products, please feel free to contact us.

Wholesale Capacity Touch Motion Sensor Switch