Beyond Eyes and Ears: How Sensors Are Transforming Our World

If the intelligent system is likened to a “being,” then the sensor serves as its sensory apparatus. Diverse sensors discern the surrounding milieu and relay data to the system for computation, enabling real-time analysis, discernment, and response to the circumstances. As digital intelligence continues to advance, the utilization of various sensors has undergone significant expansion, exerting a profound influence on the enhancement of human existence.

A plethora of sensors inhabit a smartphone: CMOS image sensors for capturing images, ambient light sensors for assessing environmental luminosity, geomagnetic sensors and gyroscopes for navigation… It is upon these sensors that the seamless operation of myriad applications hinges, transforming mobile phones into portable intelligent devices amalgamating work, leisure, and amusement, thereby instigating substantial alterations in people’s routines. The visible and infrared photoelectric sensors aboard the Fengyun satellite procure atmospheric data both day and night, enabling precise weather forecasting. Sensors even operate on the lunar and Martian surfaces, facilitating human exploration of the cosmos.

In 1821, scientists leveraged the principle of materials generating voltage differentials due to temperature disparities to fabricate the world’s inaugural sensor, a temperature sensor. Initially, physical phenomena such as light, heat, electricity, force, and magnetism were directly exploited in the creation of various sensors. These sensors were voluminous, lacked sensitivity, and proved unwieldy in use. In the 1970s, integrated sensors comprising sensitive components and signal circuits emerged, including thermocouple sensors, Hall sensors, and photosensitive sensors. Such sensors comprise solid-state components such as semiconductors, dielectrics, and magnetic materials, yielding analog signals. Since the close of the preceding century, digital sensors have undergone rapid advancement, effectuating digital signal output via analog-to-digital conversion modules. Digital sensors integrate intelligent processing units capable of autonomously gathering and processing data, and adjusting operational parameters in accordance with the surroundings. The photosensitive elements within digital cameras epitomize this evolution.

By and large, sensors operate on the premise that the electrical characteristics of certain substances undergo alteration in response to environmental stimuli. For instance, platinum exhibits variable resistivities at differing temperatures, silicon’s resistance diminishes under visible light exposure, and quartz engenders charges on its surface when subjected to pressure. By exploiting the correlation between resistance and temperature, a temperature sensor can be devised, with a thermal insulation structure optionally appended to the sensitive component. Building upon the relationship between the temperature fluctuation of the sensitive component and infrared radiation energy, an infrared sensor can be fashioned. Extending from this foundation, a non-contact temperature measurement sensor can also be fabricated predicated on the interplay between target temperature and infrared radiation energy. The familiar forehead thermometer gun utilized for body temperature measurement capitalizes on this principle. Harnessing a wealth of physical and chemical effects, humans have concocted an array of formidable sensors such as “electronic noses,” surpassing canine olfactory sensitivity by a factor of 1,000, capable of detecting gas molecules, and infrared cameras adept at nocturnal object observation.

Sensor technology has emerged as the vanguard of research in the realm of high-end information devices globally, assuming an indispensable role in artificial intelligence, smart urban development, 5G communications, aerospace endeavors, life sciences, and healthcare, among other domains.

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