How does it work? | Motion sensor

Date:

2017-11-02 17:00:06

Views:

2821

Rating:

1Like 0Dislike

Share:

How does it work? | Motion sensor Source:

The motion Sensors are widely used in security systems to detect intrusion, as well as for automation of lighting and HVAC equipment in homes and offices. Analysts expect growth in the use of motion sensors by 14% annually until 2020. The largest growth is expected in Europe and Russia in the sphere of protection from outside penetration in the home automation framework. How does the motion sensor — this was in today's issue!

Motion sensors based on the analysis of various wave types coming from the environment. Depending on the type of the applied wave motion sensors are infrared, radio wave, ultrasonic and combined.

The Principle of operation infrared motion sensor based on the determination of the object temperature which differs from ambient temperature. Infrared or thermal radiation is focused by special optical system — a Fresnel lens — and is directed to sensitive semiconductor element — a pyroelectric material. This causes a change of electric potential of a pyroelectric material, which is processed by a special algorithm and leads to the activation of the fire alarm. That the sensor did not react on a heated, but stationary objects, lenses break detection zone of the sensor into several separate beams. The sensor is triggered in that case, if the object consistently crosses a few rays. While moving with very low speed may not fix the system.

The Principle of ultrasonic motion sensor based on sound locations. The basis for such a sensor is a sound generator that produces oscillations with a frequency of 25-40 kHz. They are not audible to the human ear, but, like all sound waves are reflected from obstacles and come back to the source. The motion sensor has the emitter oscillation and a microphone, which senses the reflected signal. In accordance with the Doppler effect any body that crosses the radiation flux changes the interference pattern. Therefore, the frequency of the reflected signal will differ from the radiated frequency. As emitter and receiver elements are used piezoelectric.

The radio-Wave motion sensor works on the same principle as ultrasound, only instead of audio frequency microchip generates microwave radiation with a frequency of 2.5 GHz. If the area of wave propagation there is a moving object, change the length and frequency of the wave that defines the receiver. Radio waves can pass through non-metallic barriers, for example through the walls and wooden furniture, in addition, they are quite expensive. Because they are commonly used to monitor large commercial areas, such as behind the warehouses.

To avoid false positives, used a combination of sensors. Usually one device combined infrared and radio wave sensors. This circuit has high noise immunity, reliability and lack of false positives.

Recommended

Mystery of the Sargasso sea, and why there were dead ships

Mystery of the Sargasso sea, and why there were dead ships

At the time, in the Sargasso sea lost a lot of ships. Almost all mystical place, about which people say, giving them a mysterious halo, are on the water. When ”ends”, the disappearances do seem very strange and inexplicable. One of the places that ar...

An air leak site has been found on the ISS. What's next?

An air leak site has been found on the ISS. What's next?

Air leak occurs in Russian station module Inside the International Space Station live astronauts from different countries and all of them need oxygen. The air needed for the life of the crew is produced by special equipment, but the tightness of the ...

Why can thinking about death make life happier?

Why can thinking about death make life happier?

Awareness of one's own mortality can be a liberating and awakening experience How do you feel about the idea of death? How often do you think about it and what emotions do you feel? Many of us have been pondering these questions lately. The pandemic ...

Comments (0)

This article has no comment, be the first!

Add comment

Related News

How does it work? | Machine translation

How does it work? | Machine translation

for the First time the idea of using electronic computers for the translation of texts was expressed in 1947 in the United States, immediately after the appearance of the first computer. The first public demonstration of machine t...

How does it work? | Computer vision

How does it work? | Computer vision

As an independent discipline computer vision originated in the early 50-ies of the last century. In 1951 John von Neumann proposed to analyze microsemi using computers by comparing the brightness of adjacent parts of the image. In...

How does it work? | Search engine

How does it work? | Search engine

the First computer program for searching the Internet was Archie, created in 1990 by students from Montreal. She downloaded a list of all files from all FTP servers and build a database that you can search for file names. The firs...

How does it work? | Accelerometer

How does it work? | Accelerometer

Accelerometer — it is a sensor for measuring acceleration. It was invented in the late 19th century and was intended for installation in cars and locomotives to control the speed. The first accelerometers were heavy and bulk...

How does it work? | Holographic display

How does it work? | Holographic display

the First hologram was obtained by the Hungarian physicist Denison Gabor in 1947 in the course of the experiments to increase the resolution of electron microscopes. He coined the word "hologram", wanting to emphasize the complete...

How does it work? | E-Ink-display

How does it work? | E-Ink-display

Electronic paper was first developed at the Research Center of Xerox in Palo Alto Nick Sheridana in the 70-ies of the last century. The first electronic paper, called Gyricon, consisted of polyethylene spheres between 20 and 100 m...

How does it work? | OLED display

How does it work? | OLED display

In the last issue we about the LCD display. Today we will focus on a different technology, called OLED. So, how does the display on the organic light emitting semiconductors — this was in today's issue! the Main difference...

How does it work? LCD display

How does it work? LCD display

Liquid crystals were discovered in 1888 by Austrian scientist Friedrich Reinitzer, and in 1927, a Russian physicist Vsevolod Frederiks was discovered crossing, was named after him and is now widely used in conventional LCD display...

How does it work? | LSD-display

How does it work? | LSD-display

Liquid crystals were discovered in 1888 by Austrian scientist Friedrich Reinitzer, and in 1927, a Russian physicist Vsevolod Frederiks was discovered crossing, was named after him and is now widely used in conventional LCD display...

Nobel laureate in Economics: bitcoin is just another bubble

Nobel laureate in Economics: bitcoin is just another bubble

Robert Shiller is an American economist, has published a number of scientific papers and books on Economics. In 2013, Schiller was the winner of the Nobel prize in Economics. At the moment a scientist teaches the subject at Yale U...

Chess puzzles is worth a million dollars

Chess puzzles is worth a million dollars

One of the most ancient Board games, chess is not only developing tactical thinking, but also to improve other useful skills. For example, there are many logical brainteasers on the arrangement of pieces on a chess Board in a cert...

How does it work? | NFC-chip

How does it work? | NFC-chip

the History of NFC technology takes its beginning in 1983. Then electrical engineer Charles Walton received a patent for "portable radio frequency emitter-ID". Almost 20 years later, in March 2004, Nokia, Sony and Royal Philips El...

At Kaspersky Lab has predicted the future of Moscow

At Kaspersky Lab has predicted the future of Moscow

In anticipation of the 870 anniversary of the capital of Russia on the website of Kaspersky Lab there is a very interesting forecast for the Moscow of the future. In the framework of the project «Earth 2050» the experts ...

The head of the company Samsung will spend five years in prison

The head of the company Samsung will spend five years in prison

we have Previously that the billionaire and Vice-President of the South Korean company Samsung Electronics Li Geen was arrested on suspicion of giving multimillion-dollar bribes to government officials. If Jean is the son of the C...

How does it work? | Bank card

How does it work? | Bank card

First Bank cards appeared in America in the late 19th century. They were made of cardboard and have served only to confirm the creditworthiness of the owner outside the Bank. In 1914, Western Union issued the first card with a fix...

"Smart" sticker will indicate spoiled food

we All used to trust (or not trust) labels on food products indicating the expiration date. But unscrupulous sellers are finding ways around this system in order not to lose benefits and to sell to the buyer outstanding product. P...

How does it work? | Money counter

How does it work? | Money counter

Welcome to Hi-News.ru! First paper money appeared in China in 910 year — they replaced the metal bars. For a long time, the counting of bills can be done only manually, and only in 1908 in an attempt to optimize this process...

How does it work? | Banknote detector

How does it work? | Banknote detector

to Manufacture counterfeit money began in the days of Ancient Egypt. With the advent of banknotes, the task of the counterfeiters has been simplified, and States have begun to develop special protections that would be difficult to...

How does it work? | Facial recognition system

How does it work? | Facial recognition system

Man is able to recognize faces of other people due to the area of the brain on the border of the occipital and temporal lobe fusiform gyrus. People are learning to recognize faces from birth and at four months can clearly distingu...

How does it work? | ATM

How does it work? | ATM

a prototype of the first ATM machine was invented by the American scientist Luther Simpana in 1939. The device gave out cash, but could not deduct them from the account: the device was not associated with the Bank. In 1967 in Lond...