A sensor is a detection device that can perceive the measured information and convert the detected information into electrical signals or other required forms of information output according to certain rules, so as to meet the requirements of information transmission, processing, storage, display, recording and control. It is the primary link to realize automatic detection and automatic control.
In a narrow sense, a sensor is defined as a device or apparatus that can convert external non-electrical information into electrical signal output. In a broad sense, a sensor is defined as "any device or apparatus that uses certain material (physical, chemical, biological) principles, theorems, laws, effects, etc. to conduct energy conversion and information conversion, and whose output and input have a strict one-to-one correspondence can be called a sensor".
In the information-based 21st century, we cannot do without sensors. Sensors have a very wide range of application fields, including electronic computers, production automation, modern information, national defense, transportation, chemistry, environmental protection, energy, ocean development, remote sensing, aerospace and so on. The following is a brief introduction to some commonly used sensors.
At present, the earth's air pollution, water pollution and noise have seriously damaged the earth's ecological balance and the living environment on which we depend. This situation has attracted the attention of countries all over the world. In order to protect the environment, various environmental monitoring instruments made of sensors are playing a positive role.
China's current environment has been greatly polluted, mainly due to the development of industry. Water areas such as the Yangtze River and the Yellow River have been polluted to varying degrees; the current air is not fresh, especially in areas with industry, such as excessive PM2.5; all these are detected by sensors.
At present, robots have gradually been used to replace humans in places with heavy labor intensity or dangerous operations. Some high-speed and high-precision tasks are also very suitable for robots to undertake. However, most of these robots are used for processing, assembly, inspection and other work, and they are single-function automatic mechanical robots for production. Only sensors for detecting the position and angle of the robot arm are used on these robots.
To make robots more similar to humans in function so that they can engage in more demanding work, robots are required to have judgment ability. This requires installing object detection sensors on robots, especially visual sensors and tactile sensors, so that robots can recognize and detect objects through vision, and generate pressure, force, sliding and weight sensations on objects through touch. Such robots are called intelligent robots. They can not only engage in special operations, but also handle general production, affairs and housework. This is one of the main research objects in the development of robots now.
Sensors are widely used in modern household appliances. Sensors have been widely applied in electronic stoves, automatic rice cookers, vacuum cleaners, air conditioners, electronic water heaters, hot air heaters, air dryers, alarms, electric irons, electric fans, game consoles, electronic mosquito repellents, washing machines, dishwashers, cameras, refrigerators, color and flat-panel televisions, video recorders, tape recorders, radios, video disc players and home theaters.
With the continuous improvement of people's living standards, there is an extremely strong demand for improving the functions and automation level of household appliance products. To meet these requirements, first of all, high-precision sensors that can detect analog quantities should be used to obtain correct control information, and then controlled by microcomputers, so that household appliances are more convenient, safe, reliable, and reduce energy consumption, creating a comfortable living environment for more families.
At present, the blueprint of home automation is being designed. In the future, families will use microcomputers of central control devices to monitor various states of the home instead of humans through various sensors, and conduct various controls through control equipment. The main contents of home automation include: security monitoring and alarm, air conditioning and lighting control, energy consumption control, automatic solar tracking, housework automation and personal health management. The realization of home automation can allow people to have more time for learning, education or leisure and entertainment.
The Internet of Things is a network based on information carriers such as the Internet and traditional telecommunications networks, enabling all ordinary physical objects that can be independently addressed to achieve interconnection and intercommunication. It has three important characteristics: generalization of ordinary objects into devices, interconnection of autonomous terminals, and intelligence of universal services.
The Internet of Things (IoT) refers to the realization of machine-to-machine (M2M) communication, grand integration of applications, and software-as-a-service (SaaS) operation based on cloud computing, through various wireless/wired long-distance/short-distance communication networks, by connecting ubiquitous end devices and facilities (including sensors with "intrinsic intelligence", mobile terminals, industrial systems, building control systems, home intelligent facilities, video surveillance systems, etc.) and "externally enabled" items such as various assets with RFID tags, individuals and vehicles with wireless terminals (called "intelligent objects or animals" or "smart motes"). It provides secure, controllable and even personalized real-time online monitoring, positioning and traceability, alarm linkage, scheduling and command, plan management, remote control, safety prevention, remote maintenance, online upgrade, statistical reports, decision support, leadership dashboard (centralized display cockpit dashboard) and other management and service functions, so as to realize the integrated "management, control and operation" of "all things" with "high efficiency, energy conservation, safety and environmental protection". In short, the Internet of Things is the information transmission and control between objects, and between humans and objects. Among the three key technologies in IoT applications, sensor technology is included.
With the development of medical electronics, the era when diagnosis relies solely on doctors' experience and feeling will come to an end. Now, medical sensors can be used for high-difficulty diagnosis of human surface and internal temperature, blood pressure and intracavitary pressure, blood and respiratory flow, tumors, blood analysis, pulse and heart sounds, cardio-cerebral electrical waves, etc. Obviously, sensors play a very important role in promoting the high development of medical technology.
In order to improve the health level of the country's people, China's medical system reform will expand the target of medical services to the whole people. In the past, medical work was limited to focusing on disease treatment. In the future, medical work will play a role in a wide range of areas such as early diagnosis of diseases, early treatment, remote diagnosis and the development of artificial organs, and sensors will be used more and more in these aspects.
Satellite remote sensing is a component of aerospace remote sensing. It uses artificial earth satellites as remote sensing platforms and mainly uses satellites to conduct optical and electronic observations of the earth and the lower atmosphere. That is, it is a comprehensive technology that detects the electromagnetic wave (radiation) information on the earth's surface through sensors from different working platforms far away from the ground (such as high towers, balloons, aircraft, rockets, artificial earth satellites, spacecraft, space shuttles, etc.), and detects and monitors the earth's resources and environment through information transmission, processing, interpretation and analysis.
The sensors used on aircraft and aerospace vehicles are near-ultraviolet, visible light, far-infrared and microwave sensors. Ultrasonic sensors are mostly used for underwater observation on ships. For example, to detect in which areas some mineral resources are buried, we can use the infrared receiving sensors on artificial satellites to measure the amount of infrared rays emitted from the ground, then the artificial satellites send the data to the ground station via microwave, and after processing by the ground station computer, we can judge the areas with mineral deposits according to the differences in infrared distribution.
Nowadays, battlefields are all information-based battlefields, and informationization is inseparable from sensors. National defense experts believe that the level of a country's national defense sensor manufacturing technology determines the level of its national defense manufacturing, the level of its national defense automation, and ultimately determines the quality of its national defense equipment performance. Today, sensors are extremely widely used in national defense. It can be said that they are used at all times and everywhere, ranging from large equipment systems such as celestial bodies, nuclear weapons, aircraft, ships, tanks and artillery to individual combat weapons; from participating in national defense systems to logistical support; from national defense scientific experiments to national defense equipment engineering; from battlefield operations to strategic and tactical command; from war preparation, strategic decision-making to war implementation. They cover the entire combat system and the whole process of war. Moreover, they will definitely expand the time domain, air domain and frequency domain of combat in future high-tech wars, further affect and change the way and efficiency of combat, and greatly improve the power of national defense, as well as the combat command and battlefield management capabilities.
From the above, it can be seen that sensors are widely used in our lives and can be said to be everywhere.
