I measured my height yesterday, and I'm a little skeptical.

The receiver should be a very sensitive infrared sensor.

The temperature measuring pen uses He-Ne light-emitting diode to emit red light (not infrared, but invisible to human eyes) in a special frequency band, which shines on the object. The reflectivity and signal attenuation of objects at different temperatures are different, and the returned optical signals are received and analyzed by the tester, thus realizing temperature testing.

Infrared sensor

Infrared sensor

A sensor that uses the physical characteristics of infrared rays to measure. Infrared light, also known as infrared light, has the characteristics of reflection, refraction, scattering, interference and absorption. Any substance can radiate infrared as long as it has a certain temperature (higher than absolute zero). The infrared sensor is not in direct contact with the measured object, so there is no friction, and it has the advantages of high sensitivity and fast response.

The infrared sensor includes an optical system, a detection element and a conversion circuit. Optical systems can be divided into transmission type and reflection type according to different structures. According to the working principle, detection elements can be divided into thermal detection elements and photoelectric detection elements. Thermistor is the most widely used thermistor. When the thermistor is irradiated by infrared rays, the temperature rises, the resistance changes, and the thermistor is converted into an electrical signal for output through the conversion circuit. Photoelectric detection elements are commonly used photosensitive elements, which are usually made of ternary alloys doped with lead sulfide, lead selenide, indium arsenide, antimony arsenide, mercury cadmium telluride, germanium and silicon.

Infrared sensors are often used in non-contact temperature measurement, gas composition analysis and nondestructive testing, and are widely used in medicine, military, space technology and environmental engineering. For example, infrared sensors can be used to remotely measure the thermal image of human body surface temperature, so as to find out the abnormal temperature parts and diagnose and treat diseases in time (see thermal imager); Using infrared sensors on artificial satellites to monitor the earth's clouds can realize a wide range of weather forecast; Infrared sensors can be used to detect whether the running engine on the plane is overheated.

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The visible light that human eyes can see is arranged from long to short wavelength, which is red, orange, yellow, green, cyan, blue and purple in turn. The wavelength range of red light is 0.62 ~ 0.76 micron; The wavelength range of violet light is 0.38 ~ 0.46 μ m, the light with shorter wavelength than violet light is called ultraviolet light, and the light with longer wavelength than red light is called infrared light. In the broadest sense, a sensor is a device that can convert physical or chemical quantities into easy-to-use electrical signals, and infrared sensors are one of them. With the development of modern science and technology, infrared sensors have been widely used. The application of infrared sensor is briefly introduced through several examples. Introduction and application of pyroelectric infrared sensor for human body Working principle and characteristics of passive pyroelectric infrared probe: Generally, human body temperature is constant, generally at 37 degrees, so it will emit infrared rays with a specific wavelength of about 10UM. The working principle of passive infrared probe is to detect infrared rays emitted by human body. The infrared ray emitted by human body is about 10UM, which is enhanced by Finuer filter and concentrated on the infrared sensor. The infrared induction source usually adopts pyroelectric elements. When the temperature of infrared radiation emitted by human body changes, it will lose the charge balance and release the charge, and the electric follow-up circuit will generate an alarm signal after detection and processing. 1) This probe is designed to detect human radiation. Therefore, thermoelectric elements must be very sensitive to infrared radiation with a wavelength of about 10UM. 2) In order to be sensitive only to the infrared radiation of human body, its radiation surface is usually covered with a special Finier filter, so that the environmental interference is obviously controlled. 3) Passive infrared probe, whose sensor includes two thermoelectric elements connected in series or in parallel. Moreover, the two polarization directions are just opposite, and the environmental background radiation has almost the same effect on the two pyroelectric elements, so that their discharge effects cancel each other out, so the detector has no signal output. 4) Once someone intrudes into the detection area, the infrared radiation of human body is focused by some mirrors and received by pyroelectric elements, but the heat received by the two pyroelectric elements is different, and the pyroelectric is also different, which cannot be offset, and an alarm is given after signal processing. 5) According to different performance requirements, the fresnel filter has different focal lengths (sensing distances), resulting in different monitoring fields of view. The wider the field of vision, the tighter the control. Passive pyroelectric infrared detectors are widely used in electronic anti-theft and human body detectors, and are welcomed by users and professionals because of their low price and stable technical performance. The sensor in the infrared remote control mouse has a plastic ball exposed at the bottom of the mechanical mouse. When the mouse moves on the operating desktop, the ball rotates with it. There are three rollers in the mouse that are in contact with the ball, two of which are X-axis rollers and Y-axis rollers, which are used to measure the movement in the X-axis direction and Y-axis direction respectively, and the other is an idle shaft, which only plays a supporting role. When dragging the mouse, because the ball drives the three rollers to rotate, the rollers in the X-axis direction and the Y-axis direction each drive a rotating shaft (called the decoding wheel) to rotate. Both sides of the decoding wheel (see figure 1) are respectively equipped with infrared light-emitting diodes and photosensitive sensors to form a photoelectric coupler. Two phototransistors A and B are vertically arranged inside the photoelectric sensor, as shown in Figure 2. Because there is a gap on the decoding wheel, when the decoding wheel rotates, the infrared light emitted by the infrared light-emitting diode sometimes shines on the photosensitive sensor, and sometimes it is blocked, so that the photosensitive sensor outputs a pulse signal. The positions of phototransistors A and B make the illumination and blocking time different, so the generated pulse A and pulse B have a certain phase difference. By using this method, you can measure the dragging direction of the mouse. The infrared sensor in the camera-night vision function infrared night vision, that is, in the night vision state, the digital camera will emit infrared rays invisible to the naked eye to illuminate the subject, and turn off the infrared filter. Infrared rays are no longer blocked from entering the CCD, but are reflected by the object and enter the lens for imaging. At this time, what we see is an image reflected by infrared rays, not an image reflected by visible light, that is, we can shoot an image that is invisible to the naked eye in a dark environment at this time. Sony digital camera pioneered the infrared night vision photography function, which can shoot in all-black environment, even objects that can't be clearly distinguished by naked eyes can now be clearly photographed. The characteristic of this kind of night vision is that it can be shot without light at all, but because infrared photography is adopted, the color cannot be restored, so the shot picture is monochrome and the image will turn green. Soon after, Sony introduced a digital camera with infrared night vision function. The slow shutter with infrared function is a two-stage choice, and the slow shutter with ultra-infrared night vision function is automatically adjusted, which can obtain better image effect. For example, when the United States attacked Iraq, most parts of the Iraqi capital were in a state of power failure. At this time, in addition to the fire caused by air defense tracer and missile explosion, only moonlight or starlight shines, and the visibility is extremely poor. The pictures of the videos we saw from the scene on TV news are all green, which shows that TV reporters used infrared night vision equipment when shooting, which led to the green picture. If we don't use infrared camera technology, then we will only hear the sound from the TV picture and see no influence. It should be noted that the premise of infrared night vision camera is that digital camera can emit invisible infrared rays to illuminate the subject, so its shooting distance is limited. If the infrared rays emitted by the camera can't reach the object being photographed, then of course nothing can be photographed. Application of infrared sensor of C-2 1 1D miniature black-and-white infrared camera in engineering -Rota-Sondets infrared sleeve scanner. It can accurately measure the looper size of wire and bar production line, and even for special steel or non-ferrous metals, it can work reliably in the case of serious water vapor and smoke. Delta infrared sensor TS2006 can be used for looper control, centering control of hot rolled strip or hot plate, and provide position information in other wide applications. ?The sensitivity of infrared department detection -250℃ or 400℃ makes it simple and convenient to use, with self-monitoring and alarm functions. TS 2006 detects the position of high-temperature workpieces (steel, copper, alloy and glass, etc.). ) and outputs a signal proportional to the angular position of the workpiece in the field of view. Rota-Sorota-Sondede TS 2006 is a kind of measuring sensor working in scanning mode, which is sensitive to the infrared radiation of hot workpieces with temperatures higher than 250 C (480 F). Main features: high sensitivity: 400 C/750 F or 250 C/480 F infrared spectrum: 1 to 3? M. digital control through self-monitoring function. No optical adjustment is required. Easy to use and maintain. Designed for the harsh working environment of steel industry. The photoelectric circuit is placed in a heavy-duty housing (IP66). Provide air purification device and water cooling system. A connector and cable with a braided stainless steel protective layer are provided. ROTA-SONDE TS 2006- Centering control and deviation correction control with hot steel plate. The infrared edge sensor FR50 works according to the reflection principle. The transmitter generates a beam of parallel infrared rays with a wavelength of 880 nm, which is received by the CCD elements arranged neatly on the opposite side. The processor evaluates these signals and sends the estimated actual position to the CAN bus. The sensor determines the paper edge position with 0.02 mm accuracy in the measuring range of+/-10 mm. Optical devices only receive parallel beams, thus eliminating the height fluctuation caused by position deviation. Bit scans the stain to the controller's monitoring lens and feeds back the appropriate stain information to the controller. Sensor application and military-military remote sensing technology Remote sensing literally means feeling things from a distance. Strictly speaking, it is defined as the technology of feeling an object from a distance. Broadly speaking, remote sensing is to collect some or some specific information of an object without direct contact, so as to understand the nature of this object. A long time ago, people wanted to observe the earth from the air. At that time, people used ordinary cameras, and later developed into specialized aerial cameras. The technology of aerial photography has made great progress during World War II, and the identification technology based on this photo has also been greatly improved. With the improvement of aircraft technology, especially the appearance of rockets and satellites, remote sensing technology has gained a brand-new platform. Nowadays, remote sensing technology is changing with each passing day, and it has become an indispensable and important technology in national economic construction, especially in military applications. The information collected by remote sensing is electromagnetic waves emitted or reflected by objects. These electromagnetic waves include near ultraviolet, infrared, visible light, microwave and so on. The device that collects electromagnetic wave information is called a sensor. The place where the sensor is installed is called the platform. Remote sensing is a technology that uses sensors installed on the platform to collect (measure) electromagnetic waves radiated or (and) reflected by objects, and then analyze and process these data to obtain object information. An important factor of the rapid development of remote sensing technology is its application in our living environment. People need to know more about our earth, its resources and changes in order to arrange production and living activities reasonably. The main principle of remote sensing Note: The sensor is installed on the platform, which can use electromagnetic waves in visible light and near infrared region for remote sensing, using the reflection characteristics of objects. This method is the result of the development of aerial photography, and it is also the most widely used one. Observing the earth on the moon is like this. In addition, there are two other technologies that also show their talents in remote sensing. One is to use thermal infrared and thermal imaging technology, mainly using the radiation characteristics of objects. Thermal imaging is a branch of remote sensing, which is related to the remote measurement of the temperature of the earth's surface features. The problem it studies is small enough to detect the heat leakage of a room and large enough to study the ocean current on the earth's surface. Because temperature is one of the important controlling factors of all physical, chemical and biological processes in the earth environment. Therefore, the temperature data must occupy an extremely important position in the activities of managing the earth's resources. The second is to use microwave remote sensor for remote sensing. Microwave remote sensing is divided into passive and active. The active microwave remote sensor is mainly a side-looking radar. It was developed for the purpose of military reconnaissance in 1950s. At present, its important application mainly lies in the rapid acquisition of ground resources intelligence data in large areas with clouds. Passive microwave remote sensor feels the natural available microwave energy in its field of view, and its working mode is very similar to that of thermal radiometer or thermal scanner, but the signal it can receive is much weaker than that in thermal infrared region, and the noise accompanying the signal is much greater. Therefore, it is much more difficult to interpret this signal than other remote sensors. But it also has all-weather characteristics like side-looking radar. According to the appropriate working wavelength, it can be used to penetrate the atmosphere or observe the atmosphere. Generally speaking, microwave remote sensing is used to measure all kinds of atmospheric data, and has applications in oceanography, oil pollution detection, snowmelt determination and so on. The application of remote sensing in military science is obvious, because the target can be observed from a distance and relatively macro analysis data can be obtained. Militarily, the uses of remote sensing are roughly as follows: First, monitoring the resource status of target countries and regions. By effectively monitoring resources and their changes, it can help to determine strategic goals. Second, monitor each other's military deployment and large-scale military operations. The position information of many military deployments can be obtained by high-precision satellite remote sensing, and large-scale military mobilization is also easy to leave traces on the remote sensor, providing fast and effective information for the corresponding countries to take corresponding measures. Secondly, in specific operations, remote sensing can help analyze the local topography and resources, thus helping us to judge the tactical action plan. The launch of various military satellites also provides a basis for all-round monitoring of targets. As a digital war, information is very important in modern wars, and remote sensing, as a technology that can obtain information in a wide range, with high precision and quickly, will surely be more applied in future wars. It can be seen that sensors are playing an increasingly important role in the fields of science and technology, industrial and agricultural production and daily life. The demand for sensors in human society is increasing, which is a powerful driving force for the development of sensor technology. The rapid development of modern science and technology provides a strong backing. 2 1 century, on the one hand, people improve the technical performance of sensors; On the one hand, by looking for new principles, new materials, new processes and new functions to improve the performance of sensors, more sensors are manufactured. As a part of it, infrared sensor will surely get greater development. The infrared thermometer can capture the infrared energy radiated by all objects.

Infrared radiation is a part of the electromagnetic spectrum, which includes radio waves, microwaves, visible light, ultraviolet rays, gamma rays and X rays.

Infrared is between visible light and radio waves in spectrum. The infrared wavelength is usually expressed in microns, and the infrared spectrum range is 0.7 ~ 1000 micron. In fact, the band range for infrared temperature measurement is 0.7 to 14 micron.