| A sensor is a type of transducer.
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| | pulse is proportional to the distance and
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| Direct-indicating sensors, for example, a
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| | is related to atmospheric density in a
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| mercury thermometer, are human-readable.
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| | predictable way.
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| Other sensors must be paired with an
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| | light sensors, or photodetectors,
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| indicator or display, for instance a
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| | including semiconductor devices such as
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| thermocouple. Most sensors are electrical
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| | photocells, photodiodes,
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| or electronic, although other types
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| | phototransistors, CCDs, and Image
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| exist.
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| | sensors; vacuum tube devices like
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| Sensors are used in everyday life.
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| | photo-electric tubes, photomultiplier
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| Applications include automobiles,
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| | tubes; and mechanical instruments such as
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| machines, aerospace, medicine, industry
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| | the Nichols radiometer.
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| and robotics.
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| | infra-red sensor, especially used as
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| Technological progress allows more and
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| | occupancy sensor for lighting and
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| more sensors to be manufactured on the
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| | environmental controls.
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| microscopic scale as microsensors using
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| | proximity sensor- A type of distance
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| MEMS technology. In most cases a
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| | sensor but less sophisticated. Only
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| microsensor reaches a significantly
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| | detects a specific proximity. May be
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| higher speed and sensitivity compared
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| | optical - combination of a photocell and
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| with macroscopic approaches. Types
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| | LED or laser. Applications in cell
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| Since a significant change involves an
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| | phones, paper detector in photocopiers,
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| exchange of energy, sensors can be
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| | auto power standby/shutdown mode in
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| classified according to the type of
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| | notebooks and other devices. May employ a
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| energy transfer that they detect.
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| | magnet and a Hall effect device.
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| Thermal
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| | scanning laser- A narrow beam of laser
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| temperature sensors: thermometers,
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| | light is scanned over the scene by a
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| thermocouples, temperature sensitive
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| | mirror. A photocell sensor located at an
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| resistors (thermistors and resistance
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| | offset responds when the beam is
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| temperature detectors), bi-metal
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| | reflected from an object to the sensor,
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| thermometers and thermostats
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| | whence the distance is calculated by
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| heat sensors: bolometer, calorimeter
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| | triangulation.
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| Electromagnetic
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| | focus. A large aperture lens may be
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| electrical resistance sensors: ohmmeter,
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| | focused by a servo system. The distance
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| multimeter
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| | to an in-focus scene element may be
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| electrical current sensors: galvanometer,
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| | determined by the lens setting.
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| ammeter
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| | binocular. Two images gathered on a known
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| electrical voltage sensors: leaf
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| | baseline are brought into coincidence by
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| electroscope, voltmeter
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| | a system of mirrors and prisms. The
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| electrical power sensors: watt-hour
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| | adjustment is used to determine distance.
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| meters
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| | Used in some cameras (called range-finder
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| magnetism sensors: magnetic compass,
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| | cameras) and on a larger scale in early
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| fluxgate compass, magnetometer, Hall
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| | battleship range-finder
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| effect device
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| | interferometry. Interference fringes
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| metal detectors
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| | between transmitted and reflected
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| RADAR
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| | lightwaves produced by a coherent source
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| Mechanical
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| | such as a laser are counted and the
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| pressure sensors: altimeter, barometer,
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| | distance is calculated. Capable of
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| barograph, pressure gauge, air speed
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| | extremely high precision.
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| indicator, rate of climb indicator,
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| | Scintillometers measure atmospheric
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| variometer
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| | optical disturbances.
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| gas and liquid flow sensors: flow sensor,
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| | Fiber Optic sensors
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| anemometer, flow meter, gas meter, water
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| | Ionising radiation
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| meter, mass flow sensor
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| | radiation sensors: Geiger counter,
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| mechanical sensors: acceleration sensor,
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| | dosimeter, Scintillation counter, Neutron
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| position sensor, selsyn, switch, strain
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| | detection
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| gauge
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| | subatomic particle sensors: Particle
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| Chemical
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| | detector, scintillator, Wire chamber,
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| Chemical sensors detect the presence of
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| | cloud chamber, bubble chamber. See
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| specific chemicals or classes of
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| | Category:Particle detectors
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| chemicals. Examples include oxygen
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| | Acoustic
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| sensors, also known as lambda sensors,
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| | acoustic : uses ultrasound time-of-flight
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| ion-selective electrodes, pH glass
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| | echo return. Used in mid 20th century
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| electrodes, and redox electrodes.
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| | polaroid cameras and applied also to
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| A carbon monoxide detector is a chemical
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| | robotics. Even older systems like
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| sensor often used in the home. These
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| | Fathometers (and fish finders) and other
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| detectors continually sample air and will
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| | 'Tactical Active' Sonar (Sound Navigation
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| sound an alarm if the amount of
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| | And Ranging) systems in naval
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| invisible, odorless, and potentially
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| | applications which mostly use audible
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| deadly carbon monoxide levels in our home
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| | sound frequencies.
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| and/or workplace rises above 400 PPM.
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| | sound sensors : microphones, hydrophones,
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| In manufacturing, chemical sensors are
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| | seismometers.
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| used to manage process controls, quality
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| | Other types
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| assurance, and safety.
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| | motion sensors: radar gun, speedometer,
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| The engine management systems of
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| | tachometer, odometer, occupancy sensor,
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| automobiles take information from sensors
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| | turn coordinator
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| and adjust engine parameters to achieve
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| | orientation sensors: gyroscope,
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| the best mix of fuel economy, performance
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| | artificial horizon, ring laser gyroscope
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| and emissions. Oxygen sensors have been
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| | distance sensor (noncontacting) Several
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| used in automobiles since the late
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| | technologies can be applied to sense
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| 70’s. Many areas require automobiles to
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| | distance: magnetostriction
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| pass an emissions test annually. The test
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| | Non Initialized systems
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| equipment also uses chemical sensors to
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| | Gray code strip or wheel- a number of
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| check the exhaust emissions.
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| | photodetectors can sense a pattern,
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| Chemical sensors have been developed to
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| | creating a binary number. The gray code
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| detect threats from explosives and
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| | is a mutated pattern that ensures that
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| biological weapons. Monitoring for these
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| | only one bit of information changes with
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| threats includes border crossings, major
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| | each measured step, thus avoiding
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| transportation systems, and large public
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| | ambiguities.
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| spaces.[1] For example, airport security
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| | Initialized systems
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| utilizes chemical sensors used to sniff
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| | These require starting from a known
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| out explosives and even drugs.[2]
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| | distance and accumulate incremental
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| Chemical sensors are also being developed
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| | changes in measurements.
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| to sniff out illnesses in people.[3]
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| | Quadrature wheel- An disk-shaped optical
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| In supramolecular analytical chemistry
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| | mask is driven by a gear train. Two
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| novel molecular sensors are developed for
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| | photocells detecting light passing
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| a wide range of such applications.
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| | through the mask can determine a partial
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| Optical radiation
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| | revolution of the mask and the direction
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| light time-of-flight. Used in modern
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| | of that rotation.
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| surveying equipment, a short pulse of
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| | whisker sensor- A type of touch sensor
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| light is emitted and returned by a
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| | and proximity sensor.
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| retroreflector. The return time of the
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