Sensing technology has long penetrated into a wide range of fields such as industrial production, military defense, space exploration, marine development, environmental protection, resource survey, medical diagnosis, bioengineering, cultural relics protection, security, and household appliances. Therefore, from the space to the vast ocean, from various complex engineering systems to the daily life of clothing, food and shelter, almost every field is inseparable from a variety of sensors. It is no exaggeration to say that the 21st century society will be a sensor-filled world.

In the power industry, the bearing temperature of the rotating parts of the generator set and the dynamic balance of the rotor are detected; the flow, speed, pressure and temperature of the steam turbine inlet are measured and controlled, and the power and frequency of the generator set can be adjusted to ensure the power supply quality. At the same time, the boiler water level, the pulverized coal bin level and the boiler temperature are automatically detected and controlled, and automatic coal and water are added to ensure safe production.

In the process of industrial production automation, the parameters of temperature, pressure, flow, liquid level and pH are detected, monitored and controlled, so that the equipment works in the best condition, the cost is the lowest, the product quality is the highest, and at the same time, in the production process The parameters of the link are converted into electrical signals and interfaced with the computer to achieve production automation.

In the mechanical manufacturing industry, the sensing technology is used to detect the presence or absence of bubbles and cracks in the casting. In the machining process, various sensors are used to determine the tool holder pressure, whether the workpiece is clamped, and the automatic feed amount. Control, the detection of lathe vibration, and the processing accuracy, surface finish, flatness, coaxiality, roundness, taper, etc. after the workpiece is processed, is beneficial to ensure and improve the processing quality of the workpiece.

The metallurgical department measures the temperature of liquid metal. Large steel mills need more than 20,000 sensors and automated instruments to automatically detect and control the pressure, torque, speed and on-line non-stop of the thickness of the plate. Multi-point cycle detection and control of pressure, flow, liquid level and other parameters is the key to ensuring product quality.

In aerospace technology, sensors are used much earlier. Used to detect flight parameters of aircraft and various space vehicles

Number, operating state and engine thrust, pressure of the liquid fuel nozzle of the combustion chamber, temperature, flow rate of liquid fuel in the pipeline, flow rate, energy supply of various satellites in the air, spacecraft, surveillance of ground military equipment and important buildings by reconnaissance satellites Cameras, photos, etc. are inseparable from sensors. The US Apollo 10 spacecraft uses a large number of sensors to monitor 3,295 parameters. China's "Shenzhou" spacecraft, only the Ministry of Information Industry No. 49 has provided more than 400 sets of more than 2,000 sensors to detect and control various parameters in the spacecraft.

Light industry departments such as paper, textile, and tobacco are also inseparable from sensors. Use the sensor to measure the tension of paper and yarn, check the fabric for broken yarn, and detect and control the temperature and humidity in the air, which is of great benefit to ensure the quality of paper, cotton yarn and cigarette.

In the transportation department, in order to study the strength of the aircraft, several hundred strain gauges should be attached to the wing; in the test flight, sensors should also be used to measure the parameters such as engine speed, torque, vibration, and related parts of the aircraft. Parameters such as stress, temperature, fuel flow and liquid level; the automotive industry also uses more than 30 sensors to detect parameters such as speed, azimuth, torque, vibration, oil pressure, oil quantity and temperature. More successful sensors are being used in the US and the unmanned vehicles being tested. In addition, before the flight, train, or ship, check whether there are dangerous goods or flammable products in the passenger bag, the customs check the goods in the container, and check the weight and load distribution of the goods loaded in the car and the ship. The monitoring of the safe running state of the bridge, as well as the prevention of collisions between cars, boats and airplanes driving at night, in heavy fog or in the clouds, requires the use of sensors.

On the military side, it can be said that modern warfare is a war of science and technology, that is, a sensor war. From the detection of landmines in the early 20th century to the modern missiles, from the Gulf War at the end of the 20th century to the battle between the United States and Iraq at the beginning of this century, sensor technology was used. In search of Iraq¡¯s so-called weapons of mass destruction, the United Nations weapons inspection team used sensors to search every corner of Iraq, and even military facilities hidden in the depths of nearly 100 meters underground were not spared.

In terms of medical care, many inspection instruments use sensors such as isotope scanning, B-mode ultrasound, magnetic resonance, electroencephalography, and electrocardiogram. Biosensors are also used to detect the content of sugar and uric acid in human blood to confirm the condition. There is also a very small sensor that is injected into a human blood vessel with a syringe to detect various diseases such as blood vessel wall thickness, blood pressure, blood thickening, blood clots, arteriosclerosis, and internal structure of the heart.

In terms of safety and environmental protection, sensors are used to detect forest fires, to predict earthquakes, landslides, landslides, tsunamis, to detect floods, flood peaks, and dykes, and to detect pollution levels of rivers, lakes, seawater, and air. Sensors are also used for the detection of environmental pollution caused by noise and harmful gases.

Marine engineering requires many sensors. The ocean accounts for 70% of the surface area of the earth. The ocean is a new living space that is mainly developed by humans in the 21st century. It is a treasure house with enormous natural resources and is the main battlefield for local wars under high-tech conditions in the future. To develop and utilize the ocean, you must first understand the ocean. Therefore, for the detection of seabed gravity field, magnetic field strength, topography, geological faults, mineral types and content, sensors are required for the detection of marine hydrological information, meteorological information, chemical composition and tidal currents. Especially for deep sea exploration below 5000m, it mainly depends on various sensors, because there are many minerals worth mining, such as manganese nodules. In addition, offshore oil drilling and mining also requires sensors.

In the archaeological area, sensors are used to detect historical sites, and the age of cultural relics is detected and detected. In geology exploration, sensors are used to detect underground deposits, detect radioactive elements, detect groundwater, and identify fossil formation time. In the field of bionics, bionic sensors such as electronic noses and electronic compound eyes are manufactured. As for the visual, auditory, olfactory, tactile and taste sensations of intelligent robots, the functions of human beings can be imitated, and various sensors are used.

More and more sensors are used in office appliances and household appliances, such as sensors for displacement, illumination, and temperature in copiers; temperature and humidity sensors are installed on refrigerators and air conditioners; liquid level, vibration, and Humidity sensors, pyroelectric sensors in rice cookers, gas sensors for gas leakage in range hoods, and smoke sensors for fire prevention, as well as recorders, video recorders, VCDs, televisions, sphygmomanometers, etc., require many sensors.