Sensor
![An [[infrared sensor](https://upload.wikimedia.org/wikipedia/commons/d/da/Infrared_Transceiver_Circuit.jpg)
A sensor is a device that produces an output signal for the purpose of detecting a physical phenomenon.
In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends the information to other electronics, frequently a computer processor.
Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps which dim or brighten by touching the base, and in innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms, the uses of sensors have expanded beyond the traditional fields of temperature, pressure and flow measurement, for example into MARG sensors.
Analog sensors such as potentiometers and force-sensing resistors are still widely used. Their applications include manufacturing and machinery, airplanes and aerospace, cars, medicine, robotics and many other aspects of our day-to-day life. There is a wide range of other sensors that measure chemical and physical properties of materials, including optical sensors for refractive index measurement, vibrational sensors for fluid viscosity measurement, and electro-chemical sensors for monitoring pH of fluids.
A sensor's sensitivity indicates how much its output changes when the input quantity it measures changes. For instance, if the mercury in a thermometer moves 1 cm when the temperature changes by 1 °C, its sensitivity is 1 cm/°C (it is basically the slope assuming a linear characteristic). Some sensors can also affect what they measure; for instance, a room temperature thermometer inserted into a hot cup of liquid cools the liquid while the liquid heats the thermometer. Sensors are usually designed to have a small effect on what is measured; making the sensor smaller often improves this and may introduce other advantages.
Technological progress allows more and more sensors to be manufactured on a microscopic scale as microsensors using MEMS technology. In most cases, a microsensor reaches a significantly faster measurement time and higher sensitivity compared with macroscopic approaches. Due to the increasing demand for rapid, affordable and reliable information in today's world, disposable sensors—low-cost and easy‐to‐use devices for short‐term monitoring or single‐shot measurements—have recently gained growing importance. Using this class of sensors, critical analytical information can be obtained by anyone, anywhere and at any time, without the need for recalibration and worrying about contamination. Provided by Wikipedia
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1by Schurer, K. (ed.), International Society for Horticultural Science, Wageningen (Netherlands). Commission for Horticultural Engineering eng, International Workshop on Sensors in Horticulture eng 29-31 Jan 1991 1 Noordwijkerhout (Netherlands), Institute of Agricultural Engineering, Wageningen (Netherlands) eng
Published 1991Texto bibliotecaFAO IT -
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3by Pennsylvania State Univ., University Park (USA). College of Earth and Mineral Sciences eng, Workshop on Thermal Remote Sensing of the Energy and Water Balance Over Vegetation in Conjunction with Other Sensors eng 20-23 Sep 1993 La Londe Les Maures (France), Centre d'Etude des Environnements Terrestre et Planetaires, Velizy (France) fre, Centre National du Machinisme Agricole, du Genie Rural, des Eaux et des Forets, Montpellier (France) fre
Published 1993Texto bibliotecaFAO IT