View source for Sensor

{{Short description|Converter that measures a physical quantity and converts it into a signal}}
{{Redirect|Sensors}}
{{Redirect|Detector|detector circuits in radio and other signal-related electronics|Detector (radio)}}
{{distinguish|Censor (disambiguation){{!}}Censor|Censure|Censer|Senser}}

[[File:Light sensor.png|thumb|Different types of [[light sensor]]s]]

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,<ref>{{cite book |title=A History of Control Engineering 1930–1955 |last=Bennett |first=S. |year=1993 |publisher=Peter Peregrinus Ltd. on behalf of the Institution of Electrical Engineers |location=London |isbn=978-0-86341-280-6 |postscript=The source states "controls" rather than "sensors", so its applicability is assumed. Many units are derived from the basic measurements to which it refers, such as a liquid's level measured by a differential pressure sensor.}}</ref> for example into [[Attitude and heading reference system|MARG sensors]].

Analog sensors such as [[potentiometer]]s and [[force-sensing resistor]]s 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&nbsp; cm when the temperature changes by 1&nbsp;°C, its sensitivity is 1&nbsp;cm/°C (it is basically the slope {{math|dy/dx}} 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.<ref name="yan">{{Cite book| author=Jihong Yan| title=Machinery Prognostics and Prognosis Oriented Maintenance Management| url=https://books.google.com/books?id=LbzlBQAAQBAJ&pg=PA107| page=107| year=2015| publisher=Wiley & Sons Singapore Pte. Ltd| isbn=9781118638729}}</ref>

Technological progress allows more and more sensors to be manufactured on a [[microscopic scale]] as microsensors using [[Microelectromechanical systems|MEMS]] technology. In most cases, a microsensor reaches a significantly faster measurement time and higher sensitivity compared with [[macroscopic]] approaches.<ref name=yan/><ref>{{Cite book| author=Ganesh Kumar| title=Modern General Knowledge| url=https://books.google.com/books?id=DbnFSqKSVb0C&pg=PA194| page=194| isbn=978-81-7482-180-5| publisher=Upkar Prakashan| date=September 2010}}</ref> 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.<ref name=":0">{{Cite journal|last1=Dincer|first1=Can|last2=Bruch|first2=Richard|last3=Costa‐Rama|first3=Estefanía|last4=Fernández‐Abedul|first4=Maria Teresa|last5=Merkoçi|first5=Arben|last6=Manz|first6=Andreas|last7=Urban|first7=Gerald Anton|last8=Güder|first8=Firat|date=2019-05-15|title=Disposable Sensors in Diagnostics, Food, and Environmental Monitoring|journal=Advanced Materials|volume=31|issue=30|language=en|pages=1806739|doi=10.1002/adma.201806739|pmid=31094032|issn=0935-9648|doi-access=free|hdl=10044/1/69878|hdl-access=free}}</ref>

==Classification of measurement errors==
[[File:Infrared Transceiver Circuit.jpg|thumb|An [[infrared sensor]]]]

A good sensor obeys the following rules:<ref name=":0" />

* it is sensitive to the measured property
* it is insensitive to any other property likely to be encountered in its application, and
* it does not influence the measured property.

Most sensors have a [[Linearity|linear]] [[transfer function]].  The [[sensitivity (electronics)|sensitivity]] is then defined as the ratio between the output signal and measured property. For example, if a sensor measures temperature and has a voltage output, the sensitivity is constant with the units [V/K].  The sensitivity is the slope of the transfer function.  Converting the sensor's electrical output (for example V) to the measured units (for example K) requires dividing the electrical output by the slope (or multiplying by its reciprocal).  In addition, an offset is frequently added or subtracted.  For example, −40 must be added to the output if 0 V output corresponds to −40 C input.

For an analog sensor signal to be processed or used in digital equipment, it needs to be converted to a digital signal, using an [[analog-to-digital converter]].

===Sensor deviations===
Since sensors cannot replicate an ideal [[transfer function]], several types of deviations can occur which limit sensor [[Accuracy and precision|accuracy]]:
* Since the range of the output signal is always limited, the output signal will eventually reach a minimum or maximum when the measured property exceeds the limits. The [[full scale]] range defines the maximum and minimum values of the measured property. {{citation needed|date=May 2015}}
* The [[sensitivity (electronics)|sensitivity]] may in practice differ from the value specified. This is called a sensitivity error.  This is an error in the slope of a linear transfer function.
* If the output signal differs from the correct value by a constant, the sensor has an offset error or [[bias]]. This is an error in the [[y-intercept]] of a linear transfer function.
* [[Nonlinearity]] is deviation of a sensor's transfer function from a straight line transfer function. Usually, this is defined by the amount the output differs from ideal behavior over the full range of the sensor, often noted as a percentage of the full range.
* Deviation caused by rapid changes of the measured property over time is a [[dynamics (physics)|dynamic]] error. Often, this behavior is described with a [[bode plot]] showing sensitivity error and phase shift as a function of the frequency of a periodic input signal.
* If the output signal slowly changes independent of the measured property, this is defined as [[drift (telecommunication)|drift]]. Long term drift over months or years is caused by physical changes in the sensor.
* [[Noise]] is a random deviation of the signal that varies in time.
* A [[hysteresis]] error causes the output value to vary depending on the previous input values.  If a sensor's output is different depending on whether a specific input value was reached by increasing vs. decreasing the input, then the sensor has a hysteresis error.
* If the sensor has a digital output, the output is essentially an approximation of the measured property. This error is also called [[Quantization (signal processing)|quantization]] error.
* If the signal is monitored digitally, the [[sampling frequency]] can cause a dynamic error, or if the input variable or added noise changes periodically at a frequency near a multiple of the sampling rate, [[aliasing]] errors may occur.
* The sensor may to some extent be sensitive to properties other than the property being measured. For example, most sensors are influenced by the temperature of their environment.

All these deviations can be classified as [[systematic error]]s or [[random errors]]. Systematic errors can sometimes be compensated for by means of some kind of [[calibration]] strategy. Noise is a random error that can be reduced by [[signal processing]], such as filtering, usually at the expense of the dynamic behavior of the sensor.

===Resolution===<!-- This section is redirected to from [[Sensor resolution]] -->
The ''sensor resolution'' or ''measurement resolution'' is the smallest change that can be detected in the quantity that is being measured. The resolution of a sensor with a digital output is usually the [[numerical resolution]] of the digital output. The resolution is related to the [[accuracy and precision|precision]] with which the measurement is made, but they are not the same thing. A sensor's accuracy may be considerably worse than its resolution.

* For example, the '''distance resolution''' is the minimum distance that can be accurately measured by any [[List of length, distance, or range measuring devices|distance measuring devices]]. In a [[time-of-flight camera]], the distance resolution is usually equal to the [[standard deviation]] (total noise) of the signal expressed in [[unit of length]].
* The sensor may to some extent be sensitive to properties other than the property being measured. For example, most sensors are influenced by the temperature of their environment.

==Chemical sensor==
A chemical sensor is a self-contained analytical device that can provide information about the chemical composition of its environment, that is, a [[liquid]] or a [[gas phase]].<ref>{{cite journal |last1=Toniolo |first1=Rosanna |last2=Dossi |first2=Nicolò |last3=Giannilivigni |first3=Emanuele |last4=Fattori |first4=Andrea |last5=Svigelj |first5=Rossella |last6=Bontempelli |first6=Gino |last7=Giacomino |first7=Agnese |last8=Daniele |first8=Salvatore |title=Modified Screen Printed Electrode Suitable for Electrochemical Measurements in Gas Phase |journal=Analytical Chemistry |date=3 March 2020 |volume=92 |issue=5 |pages=3689–3696 |doi=10.1021/acs.analchem.9b04818 |pmid=32008321 |s2cid=211012680 |url=https://pubs.acs.org/doi/10.1021/acs.analchem.9b04818 |issn=0003-2700}}</ref><ref>{{cite book|last=Bǎnicǎ|first=Florinel-Gabriel|title=Chemical Sensors and Biosensors:Fundamentals and Applications|year=2012|publisher=John Wiley & Sons|location=Chichester, UK|isbn=978-1-118-35423-0|page=576}}</ref> The information is provided in the form of a measurable physical signal that is correlated with the [[concentration]] of a certain chemical species (termed as [[analyte]]). Two main steps are involved in the functioning of a chemical sensor, namely, recognition and [[Signal transduction|transduction]]. In the recognition step, analyte molecules interact selectively with [[Receptor (biochemistry)|receptor molecules]] or sites included in the structure of the recognition element of the sensor. Consequently, a characteristic physical parameter varies and this variation is reported by means of an integrated [[transducer]] that generates the output signal.
A chemical sensor based on recognition material of biological nature is a [[biosensor]]. However, as synthetic [[biomimetic]] materials are going to substitute to some extent recognition biomaterials, a sharp distinction between a biosensor and a standard chemical sensor is superfluous. Typical biomimetic materials used in sensor development are [[molecularly imprinted polymer]]s and [[aptamer]]s.<ref>{{cite journal |last1=Svigelj |first1=Rossella |last2=Dossi |first2=Nicolo |last3=Pizzolato |first3=Stefania |last4=Toniolo |first4=Rosanna |last5=Miranda-Castro |first5=Rebeca |last6=de-los-Santos-Álvarez |first6=Noemí |last7=Lobo-Castañón |first7=María Jesús |title=Truncated aptamers as selective receptors in a gluten sensor supporting direct measurement in a deep eutectic solvent |journal=Biosensors and Bioelectronics |date=1 October 2020 |volume=165 |pages=112339 |doi=10.1016/j.bios.2020.112339|pmid=32729482 |hdl=10651/57640 |s2cid=219902328 |hdl-access=free }}</ref>
=== Chemical sensor array ===
{{excerpt|Chemical sensor array}}

==Biosensor==
{{Main|Biosensor}}
In [[biomedicine]] and [[biotechnology]], sensors which detect [[analyte]]s thanks to a biological component, such as cells, protein, nucleic acid or [[biomimetic polymer]]s, are called [[biosensor]]s.
Whereas a non-biological sensor, even organic (carbon chemistry), for biological analytes is referred to as sensor or [[nanosensor]]. This terminology applies for both [[in-vitro]] and in vivo applications.
The encapsulation of the biological component in biosensors, presents a slightly different problem that ordinary sensors; this can either be done by means of a [[semipermeable membrane|semipermeable barrier]], such as a [[Dialysis (chemistry)|dialysis]] membrane or a [[hydrogel]], or a 3D polymer matrix, which either physically constrains the sensing [[macromolecule]] or chemically constrains the macromolecule by bounding it to the scaffold.

==Neuromorphic sensors==
[[Neuromorphic]] sensors are sensors that physically mimic structures and functions of biological neural entities.<ref>{{Cite journal|doi=10.3389/fnins.2016.00115|doi-access=free|title=A Review of Current Neuromorphic Approaches for Vision, Auditory, and Olfactory Sensors|year=2016|last1=Vanarse|first1=Anup|last2=Osseiran|first2=Adam|last3=Rassau|first3=Alexander|journal=Frontiers in Neuroscience|volume=10|page=115|pmid=27065784|pmc=4809886}}</ref> One example of this is the [[event camera]].

==MOS sensors==
[[Metal–oxide–semiconductor]] (MOS) technology originates from the [[MOSFET]] (MOS field-effect transistor, or MOS transistor) invented by [[Mohamed M. Atalla]] and [[Dawon Kahng]] in 1959, and demonstrated in 1960.<ref name="computerhistory">{{cite journal|url=https://www.computerhistory.org/siliconengine/metal-oxide-semiconductor-mos-transistor-demonstrated/|title=1960: Metal Oxide Semiconductor (MOS) Transistor Demonstrated|journal=The Silicon Engine: A Timeline of Semiconductors in Computers|publisher=[[Computer History Museum]] |access-date=August 31, 2019}}</ref> MOSFET sensors (MOS sensors) were later developed, and they have since been widely used to measure [[physics|physical]], [[chemistry|chemical]], [[biological]] and [[Biophysical environment|environmental]] parameters.<ref name="Bergveld">{{cite journal |last1=Bergveld |first1=Piet |author1-link=Piet Bergveld |title=The impact of MOSFET-based sensors |journal=Sensors and Actuators |date=October 1985 |volume=8 |issue=2 |pages=109–127 |doi=10.1016/0250-6874(85)87009-8 |bibcode=1985SeAc....8..109B |url=https://core.ac.uk/download/pdf/11473091.pdf |issn=0250-6874}}</ref>

===Biochemical sensors===
A number of MOSFET sensors have been developed, for measuring [[physics|physical]], [[chemistry|chemical]], [[biological]], and [[Biophysical environment|environmental]] parameters.<ref name="Bergveld"/> The earliest MOSFET sensors include the open-gate field-effect transistor (OGFET) introduced by Johannessen in 1970,<ref name="Bergveld"/> the [[ion-sensitive field-effect transistor]] (ISFET) invented by [[Piet Bergveld]] in 1970,<ref>{{cite journal|author=Chris Toumazou |author2=Pantelis Georgiou |url=https://www.researchgate.net/publication/260616066 |title=40 years of ISFET technology: From neuronal sensing to DNA sequencing |journal=[[Electronics Letters]] |date=December 2011 |access-date=13 May 2016}}</ref> the [[adsorption]] FET (ADFET) [[patented]] by P.F. Cox in 1974, and a [[hydrogen]]-sensitive MOSFET demonstrated by I. Lundstrom, M.S. Shivaraman, C.S. Svenson and L. Lundkvist in 1975.<ref name="Bergveld"/> The ISFET is a special type of MOSFET with a gate at a certain distance,<ref name="Bergveld"/> and where the [[metal gate]] is replaced by an [[ion]]-sensitive [[membrane]], [[electrolyte]] solution and [[reference electrode]].<ref name="Schoning">{{cite journal |last1=Schöning |first1=Michael J. |last2=Poghossian |first2=Arshak |title=Recent advances in biologically sensitive field-effect transistors (BioFETs) |journal=Analyst |date=10 September 2002 |volume=127 |issue=9 |pages=1137–1151 |doi=10.1039/B204444G |pmid=12375833 |bibcode=2002Ana...127.1137S |url=http://juser.fz-juelich.de/record/16078/files/12968.pdf |issn=1364-5528}}</ref> The ISFET is widely used in [[biomedical]] applications, such as the detection of [[DNA hybridization]], [[biomarker]] detection from [[blood]], [[antibody]] detection, [[glucose]] measurement, [[pH]] sensing, and [[genetic technology]].<ref name="Schoning"/>

By the mid-1980s, numerous other MOSFET sensors had been developed, including the [[gas sensor]] FET (GASFET), surface accessible FET (SAFET), charge flow transistor (CFT), [[pressure sensor]] FET (PRESSFET), [[chemical field-effect transistor]] (ChemFET), [[ISFET|reference ISFET]] (REFET), [[Bio-FET|biosensor FET]] (BioFET), [[Bio-FET|enzyme-modified FET]] (ENFET) and immunologically modified FET (IMFET).<ref name="Bergveld"/> By the early 2000s, BioFET types such as the [[DNA field-effect transistor]] (DNAFET), [[Genetically modified|gene-modified]] FET (GenFET) and [[Membrane potential|cell-potential]] BioFET (CPFET) had been developed.<ref name="Schoning"/>

===Image sensors===
{{Main|Image sensor|Charge-coupled device|Active-pixel sensor}}

MOS technology is the basis for modern [[image sensor]]s, including the [[charge-coupled device]] (CCD) and the [[CMOS]] [[active-pixel sensor]] (CMOS sensor), used in [[digital imaging]] and [[digital camera]]s.<ref name="Williams">{{cite book |last1=Williams |first1=J. B. |title=The Electronics Revolution: Inventing the Future |date=2017 |publisher=Springer |isbn=9783319490885 |pages=245 & 249 |url=https://books.google.com/books?id=v4QlDwAAQBAJ&pg=PA245}}</ref> [[Willard Boyle]] and [[George E. Smith]] developed the CCD in 1969. While researching the MOS process, they realized that an electric charge was the analogy of the magnetic bubble and that it could be stored on a tiny MOS capacitor. As it was fairly straightforward to fabricate a series of MOS capacitors in a row, they connected a suitable voltage to them so that the charge could be stepped along from one to the next.<ref name="Williams"/> The CCD is a semiconductor circuit that was later used in the first [[digital video camera]]s for [[television broadcasting]].<ref>{{cite journal|last1=Boyle|first1=William S|last2=Smith|first2=George E.|date=1970|title=Charge Coupled Semiconductor Devices|journal=Bell Syst. Tech. J.|volume=49|issue=4|pages=587–593|doi=10.1002/j.1538-7305.1970.tb01790.x}}</ref>

The MOS [[active-pixel sensor]] (APS) was developed by Tsutomu Nakamura at [[Olympus Corporation|Olympus]] in 1985.<ref name=Nakamura85>{{cite journal |last1=Matsumoto |first1=Kazuya |last2=Nakamura |first2=Tsutomu |last3=Yusa |first3=Atsushi |last4=Nagai |first4=Shohei |display-authors=1|date=1985 |title=A new MOS phototransistor operating in a non-destructive readout mode |journal=Japanese Journal of Applied Physics |volume=24 |issue=5A |page=L323|doi=10.1143/JJAP.24.L323 |bibcode=1985JaJAP..24L.323M |s2cid=108450116 }}</ref> The CMOS active-pixel sensor was later developed by [[Eric Fossum]] and his team in the early 1990s.<ref name=fossum93>Eric R. Fossum (1993), "Active Pixel Sensors: Are CCD's Dinosaurs?" Proc. SPIE Vol. 1900, p. 2–14, ''Charge-Coupled Devices and Solid State Optical Sensors III'', Morley M. Blouke; Ed.</ref>

MOS image sensors are widely used in [[optical mouse]] technology. The first optical mouse, invented by [[Richard F. Lyon]] at [[Xerox]] in 1980, used a [[6 µm process|5{{nbsp}}µm]] [[NMOS logic|NMOS]] sensor chip.<ref>{{cite book |last1=Lyon |first1=Richard F. |author1-link=Richard F. Lyon |chapter=The Optical Mouse: Early Biomimetic Embedded Vision |title=Advances in Embedded Computer Vision |date=2014 |publisher=Springer |isbn=9783319093871 |pages=3–22 (3) |chapter-url=https://books.google.com/books?id=p_GbBQAAQBAJ&pg=PA3}}</ref><ref>{{cite book | chapter = The Optical Mouse, and an Architectural Methodology for Smart Digital Sensors | title = VLSI Systems and Computations | pages = 1–19 | last1=Lyon | first1=Richard F. | author1-link=Richard F. Lyon |editor1=H. T. Kung |editor2=Robert F. Sproull |editor3=Guy L. Steele | publisher=Computer Science Press |date=August 1981 | doi=10.1007/978-3-642-68402-9_1 | chapter-url=http://bitsavers.trailing-edge.com/pdf/xerox/parc/techReports/VLSI-81-1_The_Optical_Mouse.pdf| isbn = 978-3-642-68404-3 }}</ref> Since the first commercial optical mouse, the [[IntelliMouse]] introduced in 1999, most optical mouse devices use CMOS sensors.<ref>{{cite web |last1=Brain |first1=Marshall |last2=Carmack |first2=Carmen |title=How Computer Mice Work |url=https://computer.howstuffworks.com/mouse4.htm |website=[[HowStuffWorks]] |access-date=9 October 2019 |language=en |date=24 April 2000}}</ref>

===Monitoring sensors===
[[File:LiDAR_Scanner_and_Back_Camera_of_iPad_Pro_2020_-_3.jpg|thumb|A [[LIDAR]] sensor (bottom, center), as part of the camera system on an [[iPad Pro]].<ref>{{cite web |title=LiDAR vs. 3D ToF Sensors — How Apple Is Making AR Better for Smartphones |url=https://ios.gadgethacks.com/news/lidar-vs-3d-tof-sensors-apple-is-making-ar-better-for-smartphones-0280778/ |access-date=2020-04-03}}</ref>]]

MOS monitoring sensors are used for [[Smart home technology|house monitoring]], [[office]] and [[agriculture]] monitoring, [[traffic monitoring]] (including [[speed detection radar|car speed]], [[traffic jams]], and [[traffic accidents]]), [[weather station|weather monitoring]] (such as for [[rain sensor|rain]], [[wind meter|wind]], [[lightning detection|lightning]] and [[storm detection|storms]]), [[defense technology|defense]] monitoring, and monitoring [[temperature measurement|temperature]], [[humidity meter|humidity]], [[air pollution sensor|air pollution]], [[fire detection|fire]], [[health monitoring|health]], security and [[Lighting control system|lighting]].<ref name="Omura3">{{cite book |last1=Omura |first1=Yasuhisa |last2=Mallik |first2=Abhijit |last3=Matsuo |first3=Naoto |title=MOS Devices for Low-Voltage and Low-Energy Applications |date=2017 |publisher=[[John Wiley & Sons]] |isbn=9781119107354 |pages=3–4 |url=https://books.google.com/books?id=yOjFDQAAQBAJ&pg=PA3}}</ref> MOS [[gas detector]] sensors are used to detect [[carbon monoxide]], [[sulfur dioxide]], [[hydrogen sulfide]], [[ammonia]], and other [[gas]] substances.<ref>{{cite journal |last1=Sun |first1=Jianhai |last2=Geng |first2=Zhaoxin |last3=Xue |first3=Ning |last4=Liu |first4=Chunxiu |last5=Ma |first5=Tianjun |title=A Mini-System Integrated with Metal-Oxide-Semiconductor Sensor and Micro-Packed Gas Chromatographic Column |journal=Micromachines |date=17 August 2018 |volume=9 |issue=8 |pages=408 |doi=10.3390/mi9080408 |pmid=30424341 |pmc=6187308 |issn=2072-666X|doi-access=free }}</ref> Other MOS sensors include [[intelligent sensor]]s<ref name="Mead">{{cite book |editor-last1=Mead |editor-first1=Carver A. |editor-last2=Ismail |editor-first2=Mohammed |title=Analog VLSI Implementation of Neural Systems |volume=80 |date=May 8, 1989 |publisher=[[Kluwer Academic Publishers]] |location=Norwell, MA |isbn=978-1-4613-1639-8 |doi=10.1007/978-1-4613-1639-8 |url=http://fennetic.net/irc/Christopher%20R.%20Carroll%20Carver%20Mead%20Mohammed%20Ismail%20Analog%20VLSI%20Implementation%20of%20Neural%20Systems.pdf|series=The Kluwer International Series in Engineering and Computer Science }}</ref> and [[wireless sensor network]] (WSN) technology.<ref name="Oliveira">{{cite book |last1=Oliveira |first1=Joao |last2=Goes |first2=João |title=Parametric Analog Signal Amplification Applied to Nanoscale CMOS Technologies |date=2012 |publisher=[[Springer Science & Business Media]] |isbn=9781461416708 |page=7 |url=https://books.google.com/books?id=Ahl_OuKxsToC&pg=PR7}}</ref>

==See also==
{{Columns-list|colwidth=30em|
* [[Actuator]]
* [[Data acquisition]]
* [[Data logger]]
* [[Image sensor]]
* [[MOSFET]]
** [[BioFET]]
** [[Chemical field-effect transistor]]
** [[ISFET]]
* [[List of sensors]]
* [[Machine olfaction]]
* [[Nanoelectronics]]
* [[Nanosensor]]
* [[Sensing floor]]
* [[Transducer]]
* [[Wireless sensor network]]
}}

==References==
{{Reflist}}

==Further reading==
* M. Kretschmar and S. Welsby (2005), Capacitive and Inductive Displacement Sensors, in Sensor Technology Handbook, J. Wilson editor, Newnes: Burlington, MA.
* C. A. Grimes, E. C. Dickey, and M. V. Pishko (2006), Encyclopedia of Sensors (10-Volume Set), American Scientific Publishers. {{ISBN|1-58883-056-X}}
* Blaauw, F.J., Schenk, H.M., Jeronimus, B.F., van der Krieke, L., de Jonge, P., Aiello, M., Emerencia, A.C. (2016). [https://dx.doi.org/10.1016/j.jbi.2016.08.001 Let’s get Physiqual – An intuitive and generic method to combine sensor technology with ecological momentary assessments]. Journal of Biomedical Informatics, vol. 63, page 141–149.

{{Commons category|Sensors}}
{{Wiktionary}}
* http://www.cbm-sweden.se/images/Seminarie/Class_Descriptions_IDA_MEMS.pdf (see https://web.archive.org/web/20160304105724/http://www.cbm-sweden.se/images/Seminarie/Class_Descriptions_IDA_MEMS.pdf)

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[[Category:Sensors| ]]
[[Category:Transducers]]