Occupancy Sensor


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5 NEW SCHNEIDER WALL SWITCH DUAL OCCUPANCY SENSOR


5 NEW SCHNEIDER WALL SWITCH DUAL OCCUPANCY SENSOR


$500.00


10 LOT Leviton ODS10-IDW Commercial Grade Wall Mounted Occupancy Sensor, White


10 LOT Leviton ODS10-IDW Commercial Grade Wall Mounted Occupancy Sensor, White


$428.00


5PC  Bi-Level 2-In-1 Occupancy Sensor Dual Switch DWOS-JD-W Motion Detector


5PC Bi-Level 2-In-1 Occupancy Sensor Dual Switch DWOS-JD-W Motion Detector


$285.92


OSCW5P-15P - Tork PIR Occupancy Sensors(COLOR WHITE)


OSCW5P-15P – Tork PIR Occupancy Sensors(COLOR WHITE)


$179.95


5 High Bay Ceiling Sensor, Fixture Mount Line Voltage Occupancy Sensor MPC-50H-W


5 High Bay Ceiling Sensor, Fixture Mount Line Voltage Occupancy Sensor MPC-50H-W


$176.35


Honeywell Infracon Occupancy Sensor 628A  EL7628A   NEW


Honeywell Infracon Occupancy Sensor 628A EL7628A NEW


$150.00


1 CASE OF 10 WATT STOPPERS Occupancy Sensor, PIR, 800/1200W, Black


1 CASE OF 10 WATT STOPPERS Occupancy Sensor, PIR, 800/1200W, Black


$124.99


CS1001 Occupancy Sensor 24VDC Passive Infared, P&S NIB


CS1001 Occupancy Sensor 24VDC Passive Infared, P&S NIB


$94.88


HUBBELL H-MOSS Occupancy Ceiling Sensor ATU1000C


HUBBELL H-MOSS Occupancy Ceiling Sensor ATU1000C


$100.00


NEW WATT STOPPER UT-355-1 OCCUPANCY SENSOR ULTRASONIC


NEW WATT STOPPER UT-355-1 OCCUPANCY SENSOR ULTRASONIC


$95.00


New Square D SLSCUS2000 Ultrasonic Occupancy Sensor


New Square D SLSCUS2000 Ultrasonic Occupancy Sensor


$80.00


Leviton OSW12-MOW Multi-Tech Wide View Occupancy Sensor  WHITE


Leviton OSW12-MOW Multi-Tech Wide View Occupancy Sensor WHITE


$89.00


NEW  WATT STOPPER   DT 355 OCCUPANCY SENSOR    120/230/277/347 LINE VOLTAGE


NEW WATT STOPPER DT 355 OCCUPANCY SENSOR 120/230/277/347 LINE VOLTAGE


$65.00


WattStopper PW-100-G PIR Wall Occupancy Sensor


WattStopper PW-100-G PIR Wall Occupancy Sensor


$65.00


LMTO H M10 Occupancy Sensor Omnidirectional


LMTO H M10 Occupancy Sensor Omnidirectional


$69.00


NOS! COOPER GREENGATE OCCUPANCY SENSOR ONW-P-1001-MV-V


NOS! COOPER GREENGATE OCCUPANCY SENSOR ONW-P-1001-MV-V


$64.95


WATT STOPPER BZ-100 POWER PACK AND CI-200 CEILING MOUNT OCCUPANCY SENSOR NIB


WATT STOPPER BZ-100 POWER PACK AND CI-200 CEILING MOUNT OCCUPANCY SENSOR NIB


$65.00


GREENGATE COOPER CONTROLS OCCUPANCY SENSOR ZA-124


GREENGATE COOPER CONTROLS OCCUPANCY SENSOR ZA-124


$59.50


MYTECH OMNI-US500 OCCUPANCY SENSOR  *NEW*


MYTECH OMNI-US500 OCCUPANCY SENSOR *NEW*


$70.00


HUBBELL ULTRASONIC CEILING OCCUPANCY SENSOR OMNIUS500 500 sf Motion detector


HUBBELL ULTRASONIC CEILING OCCUPANCY SENSOR OMNIUS500 500 sf Motion detector


$69.99


HUBBELL OMNI DT-1000 CEILING OCCUPANCY SENSOR


HUBBELL OMNI DT-1000 CEILING OCCUPANCY SENSOR


$60.00


Lightolier Control IHS32KVA277W Occupancy Sensor Switch


Lightolier Control IHS32KVA277W Occupancy Sensor Switch


$60.00


Sensor Switch Occupancy Sensor Motion WVPDT16 NIB


Sensor Switch Occupancy Sensor Motion WVPDT16 NIB


$56.00


PW-200-W WATT STOPPER PIR WALL SWITCH SENSOR OCCUPANCY


PW-200-W WATT STOPPER PIR WALL SWITCH SENSOR OCCUPANCY


$64.95


Leviton OSSMT-GDW Multi-Technology Decora Style Wall Switch Occupancy Sensor


Leviton OSSMT-GDW Multi-Technology Decora Style Wall Switch Occupancy Sensor


$58.70


Dual Commercial Occupancy/Vacancy Sensor Wall Switch DWOS-JD Movement Detector


Dual Commercial Occupancy/Vacancy Sensor Wall Switch DWOS-JD Movement Detector


$57.00


LEVITON ULTRASONIC OCCUPANCY SENSOR ODC10-U0W


LEVITON ULTRASONIC OCCUPANCY SENSOR ODC10-U0W


$56.58


NEW MYTECH CORPORATION OMNI-US1000 CEILING MOUNT OCCUPANCY SENSOR US1000


NEW MYTECH CORPORATION OMNI-US1000 CEILING MOUNT OCCUPANCY SENSOR US1000


$60.00


CS1001 Occupancy Sensor 24VDC Passive Infared, P&S NIB


CS1001 Occupancy Sensor 24VDC Passive Infared, P&S NIB


$59.99


Leviton OSC15 10W PIR Ceiling Mount Occupancy Sensor 360 Degree


Leviton OSC15 10W PIR Ceiling Mount Occupancy Sensor 360 Degree


$59.99


Hubbell AT1277I Wall Occupancy Sensor H-Moss Ivory New


Hubbell AT1277I Wall Occupancy Sensor H-Moss Ivory New


$55.00


Leviton ODS10-IDW Commercial Grade Wall Mounted Occupancy Sensor Switch White


Leviton ODS10-IDW Commercial Grade Wall Mounted Occupancy Sensor Switch White


$59.00


Bi-Level 2-In-1 Occupancy Sensor Dual Switch DWOS-JD-W Motion Detector


Bi-Level 2-In-1 Occupancy Sensor Dual Switch DWOS-JD-W Motion Detector


$58.35


Leviton ODS10-IDW Commercial Grade Wall Mounted Infrared Occupancy Sensor


Leviton ODS10-IDW Commercial Grade Wall Mounted Infrared Occupancy Sensor


$49.97


LEVITON OSC05-U0W Ceiling Mount Occupancy Sensor NEW OUT OF BOX READ


LEVITON OSC05-U0W Ceiling Mount Occupancy Sensor NEW OUT OF BOX READ


$55.00


Watts Stopper UT 355-2 Occupancy Sensor


Watts Stopper UT 355-2 Occupancy Sensor


$50.00


NEW Watt Stopper UT-300-2 360 Occupancy Sensor


NEW Watt Stopper UT-300-2 360 Occupancy Sensor


$49.00


Pass Seymour CS1001 Passive Infared Occupancy Sensor


Pass Seymour CS1001 Passive Infared Occupancy Sensor


$50.00


NIB WATT STOPPER DT-200 VERSION 2 OCCUPANCY SENSOR


NIB WATT STOPPER DT-200 VERSION 2 OCCUPANCY SENSOR


$50.00


NEW! PASS & SEYMOUR Occupancy Sensor, WSP200-LA


NEW! PASS & SEYMOUR Occupancy Sensor, WSP200-LA


$50.00


The Watt Stopper Occupancy sensor infrared CX-105-4 New


The Watt Stopper Occupancy sensor infrared CX-105-4 New


$39.99


WPIR WATT STOPPER PASSIVE INFRARED OCCUPANCY SENSOR NEW


WPIR WATT STOPPER PASSIVE INFRARED OCCUPANCY SENSOR NEW


$49.95


NEW WATT STOPPER CX-100 OCCUPANCY SENSOR PASSIVE INFRARED +24VDC !


NEW WATT STOPPER CX-100 OCCUPANCY SENSOR PASSIVE INFRARED +24VDC !


$49.75


LEVITON OSC10-U0W Ceiling Mount Occupancy Sensor NEW OUT OF BOX READ


LEVITON OSC10-U0W Ceiling Mount Occupancy Sensor NEW OUT OF BOX READ


$49.00


Leviton OSC04-IOW Occupancy Infrared Ceiling Sensor Save Energy and Money


Leviton OSC04-IOW Occupancy Infrared Ceiling Sensor Save Energy and Money


$49.00


HUBBELL OMNI DT-500 DUAL TECHNOLOGY CEILING OCCUPANCY SENSOR


HUBBELL OMNI DT-500 DUAL TECHNOLOGY CEILING OCCUPANCY SENSOR


$40.00


LOT OF (4) NIB MYTECH OCCUPANCY SENSORS LAS-2200 SF LAS 2200 SF


LOT OF (4) NIB MYTECH OCCUPANCY SENSORS LAS-2200 SF LAS 2200 SF


$32.99


LEVITON NiB Occupancy Sensor, Passive Infrared, Cold Storage, 3 Lenses OSFHU-CTW


LEVITON NiB Occupancy Sensor, Passive Infrared, Cold Storage, 3 Lenses OSFHU-CTW


$40.99


CX-105-1 WATT STOPPER OCCUPANCY SENSOR PASSIVE INFRARED 24VDC CX105


CX-105-1 WATT STOPPER OCCUPANCY SENSOR PASSIVE INFRARED 24VDC CX105


$44.95


Leviton OSSMT-GDW Multi Technology Decora Motion Wall Switch Occupancy Sensor


Leviton OSSMT-GDW Multi Technology Decora Motion Wall Switch Occupancy Sensor


$39.95


LEVITON OSP-20 D0 BLACK OCCUPANCY SENSOR POWER PACK


LEVITON OSP-20 D0 BLACK OCCUPANCY SENSOR POWER PACK


$39.95


Watt Stopper Dual Technology Occupancy  Sensor DT-200 40 kHZ 24Vdc


Watt Stopper Dual Technology Occupancy Sensor DT-200 40 kHZ 24Vdc


$19.99


Leviton OSW12-M0W Occupancy Sensor


Leviton OSW12-M0W Occupancy Sensor


$30.00


Leviton OSW12-M0W Occupancy Sensor


Leviton OSW12-M0W Occupancy Sensor


$30.00


NEW Ultrasonic Occupancy Sensor Watt Stopper Model#  WT-2205 FREE SHIPPING


NEW Ultrasonic Occupancy Sensor Watt Stopper Model# WT-2205 FREE SHIPPING


$40.00


Leviton Designer Occupancy Sensor Wall Switch


Leviton Designer Occupancy Sensor Wall Switch


$40.00


LEVITON Occupancy Sensor, Passive Infrared, OSFHU-14w


LEVITON Occupancy Sensor, Passive Infrared, OSFHU-14w


$30.00


New Cooper Greengate Occupancy Sensor Wall Switch OSW-DT-0601-MV V (Ivory)


New Cooper Greengate Occupancy Sensor Wall Switch OSW-DT-0601-MV V (Ivory)


$40.00


LOT OF (5) NIB MYTECH MINI POWER PACKS FOR OCCUPANCY SENSORS MP-277A MP 277A


LOT OF (5) NIB MYTECH MINI POWER PACKS FOR OCCUPANCY SENSORS MP-277A MP 277A


$24.99


Levitron recessed ceiling occupancy sensor cat# 6778


Levitron recessed ceiling occupancy sensor cat# 6778


$34.00


NIB LEVITON OCCUPANCY SENSOR CONTROL UNIT 16773-CBX 16773 CBX


NIB LEVITON OCCUPANCY SENSOR CONTROL UNIT 16773-CBX 16773 CBX


$29.99


LEVITON ULTRASONIC OCCUPANCY SENSOR ODC10-U0W


LEVITON ULTRASONIC OCCUPANCY SENSOR ODC10-U0W


$31.98


Leviton OSP20-D0 Occupancy Sensor (NOS)


Leviton OSP20-D0 Occupancy Sensor (NOS)


$29.00


NIB WATT STOPPER WPIR VERSION 3 OCCUPANCY SENSOR


NIB WATT STOPPER WPIR VERSION 3 OCCUPANCY SENSOR


$30.00


 Low Voltage Ceiling Occupancy Motion Sensor Switch MPC-50L-W Ceiling Sensor


Low Voltage Ceiling Occupancy Motion Sensor Switch MPC-50L-W Ceiling Sensor


$35.99


 High Bay Ceiling Sensor, Fixture Mount Line Voltage Occupancy Sensor MPC-50H-W


High Bay Ceiling Sensor, Fixture Mount Line Voltage Occupancy Sensor MPC-50H-W


$35.99


The Watt Stopper WT-2255 Ultrasonic Occupancy Sensor


The Watt Stopper WT-2255 Ultrasonic Occupancy Sensor


$30.00


New Cooper Greengate OMC-DT-0701-R MicroSet Dual Tech Ceiling Occupancy Sensor


New Cooper Greengate OMC-DT-0701-R MicroSet Dual Tech Ceiling Occupancy Sensor


$35.00


Sensor Switch PP-20 Power pack & CMR 6 LT Occupancy Sensor Combo


Sensor Switch PP-20 Power pack & CMR 6 LT Occupancy Sensor Combo


$24.95


Sensor Switch PP-20 Power pack & CMR 6 LT Occupancy Sensor Combo


Sensor Switch PP-20 Power pack & CMR 6 LT Occupancy Sensor Combo


$24.95


Sensor Switch PP-20 Power pack & CMR 6 LT Occupancy Sensor Combo


Sensor Switch PP-20 Power pack & CMR 6 LT Occupancy Sensor Combo


$24.95


Leviton Ultrasonic RECESSED Ceiling  Mount Occupancy Sensor 6878-2W WHITE


Leviton Ultrasonic RECESSED Ceiling Mount Occupancy Sensor 6878-2W WHITE


$24.99


BRAND NEW LEVITON OSP20-D0 OCCUPANCY SENSOR POWER PACK 120/277V 20 AMP


BRAND NEW LEVITON OSP20-D0 OCCUPANCY SENSOR POWER PACK 120/277V 20 AMP


$25.00


LEVITON OCCUPANCY DETECTOR SENSOR POWER PACK ODP13-70


LEVITON OCCUPANCY DETECTOR SENSOR POWER PACK ODP13-70


$24.36


HUBBELL CU277A PIR WIRELESS CONTROL UNIT for OCCUPANCY SENSOR H-MOSS LOW VOLTAGE


HUBBELL CU277A PIR WIRELESS CONTROL UNIT for OCCUPANCY SENSOR H-MOSS LOW VOLTAGE


$30.00


NEW MYTECH CORPORATION LP-2 277VAC IVORY WALL SWITCH OCCUPANCY SENSOR LP2-277


NEW MYTECH CORPORATION LP-2 277VAC IVORY WALL SWITCH OCCUPANCY SENSOR LP2-277


$30.00


NEW IN BOX LEVITON OSC04-I0W INFRARED OCCUPANCY SENSOR OSC04-10W


NEW IN BOX LEVITON OSC04-I0W INFRARED OCCUPANCY SENSOR OSC04-10W


$29.99


Leviton Occupancy Motion Sensor Add-a-Relay Powerpack ODA00


Leviton Occupancy Motion Sensor Add-a-Relay Powerpack ODA00


$29.99


LOT OF (3) NIB MYTECH MINI POWER PACKS FOR OCCUPANCY SENSORS MP-277 MP 277


LOT OF (3) NIB MYTECH MINI POWER PACKS FOR OCCUPANCY SENSORS MP-277 MP 277


$14.99


Occupancy Sensor Power Pack 120/230/277 VAC MPP-24-W  Power Supply For Sensor


Occupancy Sensor Power Pack 120/230/277 VAC MPP-24-W Power Supply For Sensor


$27.00


NEW IN BOX THE WATT STOPPER WPIR VERS 3 OCCUPANCY SENSOR PASSIVE INFRARED +24VDC


NEW IN BOX THE WATT STOPPER WPIR VERS 3 OCCUPANCY SENSOR PASSIVE INFRARED +24VDC


$27.00


PASS & SEYMOUR OSC3020 OCCUPANCY SENSOR SWITCH *NEW IN A BOX*


PASS & SEYMOUR OSC3020 OCCUPANCY SENSOR SWITCH *NEW IN A BOX*


$25.00


Pass & Seymour Occupancy Sensing motion sensor switch RWU600LACCV4 NEW IN BOX


Pass & Seymour Occupancy Sensing motion sensor switch RWU600LACCV4 NEW IN BOX


$19.99


WATT STOPPER Occupancy Sensor, PIR, 800/1200W, Black


WATT STOPPER Occupancy Sensor, PIR, 800/1200W, Black


$24.50


Wattstopper A277E-P 277V Occupancy Sensor Power Pack


Wattstopper A277E-P 277V Occupancy Sensor Power Pack


$16.99


Occupancy Sensor - High Bay PIR Occupancy Sensor


Occupancy Sensor – High Bay PIR Occupancy Sensor


$19.00


Occupancy Sensor - Wall Mount PIR Vacancy/Occupancy Sensor with Night Light


Occupancy Sensor – Wall Mount PIR Vacancy/Occupancy Sensor with Night Light


$19.00


Leviton ODP20-70  Power Pack For Occupancy Sensors 277VAC 60Hz 20A( Fluorescent)


Leviton ODP20-70 Power Pack For Occupancy Sensors 277VAC 60Hz 20A( Fluorescent)


$19.95


Leviton ODP13-20 Power Pack For Occupancy Sensors 230VAC 50/60Hz 13A Fluorescent


Leviton ODP13-20 Power Pack For Occupancy Sensors 230VAC 50/60Hz 13A Fluorescent


$19.95


Occupancy Sensor - Ceiling Mount PIR Occupancy Sensor


Occupancy Sensor – Ceiling Mount PIR Occupancy Sensor


$18.00


Leviton ODA13   Occupancy Sensor Add-A-Relay   13Amps   5mA,24V DC    NIB


Leviton ODA13 Occupancy Sensor Add-A-Relay 13Amps 5mA,24V DC NIB


$19.95


Leviton  OSP20-D0 Occupancy Sensor Power Pak


Leviton OSP20-D0 Occupancy Sensor Power Pak


$10.00


Leviton  OSP20-D0 Occupancy Sensor Power Pak


Leviton OSP20-D0 Occupancy Sensor Power Pak


$10.00


Leviton  OSP20-D0 Occupancy Sensor Power Pak


Leviton OSP20-D0 Occupancy Sensor Power Pak


$10.00


Occupancy Sensor - Wall Mount PIR Occupancy Sensor - No Neutral Required


Occupancy Sensor – Wall Mount PIR Occupancy Sensor – No Neutral Required


$15.50


Novitas switchpack 13-012 For Automation Motion and occupancy sensors NEW


Novitas switchpack 13-012 For Automation Motion and occupancy sensors NEW


$19.99


 Leviton OPB15-DW OCCUPANCY SENSOR POWER BASE KIT WHITE NEW


Leviton OPB15-DW OCCUPANCY SENSOR POWER BASE KIT WHITE NEW


$19.97


Occupancy Sensor - Wall Mount PIR Occupancy Sensor


Occupancy Sensor – Wall Mount PIR Occupancy Sensor


$13.00


Leviton 500-Watt 180 degrees White Occupancy Sensor


Leviton 500-Watt 180 degrees White Occupancy Sensor


$17.99


NIB MYTECH OCCUPANCY SENSORS MAS-700 SF MAS 700 SF


NIB MYTECH OCCUPANCY SENSORS MAS-700 SF MAS 700 SF


$9.99

Occupancy Sensor Questions

Occupancy Sensor

A Role of Sensors for Industrial Applications

Since a significant change involves an exchange of energy, sensors can be classified according to the type of energy transfer that they detect. Thermal temperature sensors: thermometers, thermocouples, temperature sensitive resistors (thermistors and resistance temperature detectors), bi-metal thermometers and thermostats

heat sensors: bolometer, calorimeter

 

Electromagnetic electrical resistance sensors: ohmmeter, multimeter

Electrical current sensors: galvanometer, ammeter

Electrical voltage sensors: leaf electroscope, voltmeter

Electrical power sensors: watt-hour meters

Magnetism sensors: magnetic compass, fluxgate compass, magnetometer, Hall Effect device,

Metal detectors

 

Mechanical pressure sensors: altimeter, barometer, barograph, pressure gauge, air speed indicator, rate of climb indicator, variometer

gas and liquid flow sensors: flow sensor, anemometer, flow meter, gas meter, water meter, mass flow sensor  mechanical sensors: acceleration sensor, position sensor, selsyn, switch, strain gauge

 

Chemical sensors detect the presence of specific chemicals or classes of chemicals. Examples include oxygen sensors, also known as lambda sensors, ion-selective electrodes, pH glass electrodes, and redox electrodes.

 

Optical and radiation electromagnetic time-of-flight. Generate an electromagnetic impulse, broadcast it, and then measure the time a reflected pulse takes to return. Commonly known as – RADAR (Radio Detection And Ranging) are now accompanied by the analogous LIDAR (Light Detection And Ranging. See following line), all being electromagnetic waves. Acoustic sensors are a special case in that a pressure transducer is used to generate a compression wave in a fluid medium (air or water)

light time-of-flight. Used in modern surveying equipment, a short pulse of light is emitted and returned by a retro reflector. The return time of the pulse is proportional to the distance and is related to atmospheric density in a predictable way.

 

Ionizing radiation

 

Radiation sensors: Geiger counter, dosimeter, Scintillation counter, Neutron detection

Subatomic particle sensors: Particle detector, scintillator, Wire chamber, cloud chamber, bubble chamber

 

Non-ionising radiation

 

light sensors, or photo detectors, including semiconductor devices such as photocells, photodiodes, phototransistors, CCDs, and Image sensors; vacuum tube devices like photo-electric tubes, photomultiplier tubes; and mechanical instruments such as the Nichols radiometer. Infra-red sensor, especially used as occupancy sensor for lighting and environmental controls.

Proximity sensor- A type of distance sensor but less sophisticated. Only detects a specific proximity. May be optical – combination of a photocell and LED or laser. Applications in cell phones, paper detector in photocopiers, auto power standby/shutdown mode in notebooks and other devices. May employ a magnet and a Hall effect device.

scanning laser- A narrow beam of laser light is scanned over the scene by a mirror. A photocell sensor located at an offset responds when the beam is reflected from an object to the sensor, whence the distance is calculated by triangulation.

focus. A large aperture lens may be focused by a servo system. The distance to an in-focus scene element may be determined by the lens setting.

binocular. Two images gathered on a known baseline are brought into coincidence by a system of mirrors and prisms. The adjustment is used to determine distance. Used in some cameras (called range-finder cameras) and on a larger scale in early battleship range-finder

interferometer. Interference fringes between transmitted and reflected lightwaves produced by a coherent source such as a laser are counted and the distance is calculated. Capable of extremely high precision.

Scintillometers measure atmospheric optical disturbances.

 

Acoustic sound sensors: microphones, hydrophones, seismometers.

 

Acoustic: uses ultrasound time-of-flight echo return. Used in mid 20th century polaroid cameras and applied also to robotics. Even older systems like Fathometers (and fish finders) and other ‘Tactical Active’ Sonar (Sound Navigation And Ranging) systems in naval applications which mostly use audible sound frequencies.

 

 

Other types motion sensors: radar gun, speedometer, tachometer, odometer, occupancy sensor, turn coordinator

Orientation sensors: gyroscope, artificial horizon, ring laser gyroscope

distance sensor (non contacting) Several technologies can be applied to sense distance: magnetostriction

 

 

 

 

Non Initialized systems

 

Gray code strip or wheel- a number of photo detectors can sense a pattern, creating a binary number. The gray code is a mutated pattern that ensures that only one bit of information changes with each measured step, thus avoiding ambiguities.

 

Initialized systems

These require starting from a known distance and accumulate incremental changes in measurements.

 

Quadrature wheel- An disk-shaped optical mask is driven by a gear train. Two photocells detecting light passing through the mask can determine a partial revolution of the mask and the direction of that rotation.

whisker sensor- A type of touch sensor and proximity sensor.

 

Classification of measurement errors

A good sensor obeys the following rules:

 

the sensor should be sensitive to the measured property

the sensor should be insensitive to any other property

the sensor should not influence the measured property

In the ideal situation, the output signal of a sensor is exactly proportional to the value of the measured property. The gain is then defined as the ratio between output signal and measured property. For example, if a sensor measures temperature and has a voltage output, the gain is a constant with the unit [V/K].

 

If the sensor is not ideal, several types of deviations can be observed:

 

The gain may in practice differ from the value specified. This is called a gain error.

Since the range of the output signal is always limited, the output signal will eventually clip when the measured property exceeds the limits. The full scale range defines the outmost values of the measured property where the sensor errors are within the specified range.

If the output signal is not zero when the measured property is zero, the sensor has an offset or bias. This is defined as the output of the sensor at zero input.

If the gain is not constant, this is called nonlinearity. 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.

If the deviation is caused by a rapid change of the measured property over time, there is a dynamic error. Often, this behavior is described with a bode plot showing gain error and phase shift as 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.

Long term drift usually indicates a slow degradation of sensor properties over a long period of time. Noise is a random deviation of the signal that varies in time.

 

Hysteresis is an error caused by the fact that the sensor not instantly follows the change of the property being measured, and therefore involves the history of the measured property.

If the sensor has a digital output, the signal is discrete and is essentially an approximation of the measured property. The approximation error is also called digitization error.

If the signal is monitored digitally, limitation of the sampling frequency also causes a dynamic error.

 Sensor may to some extent be sensitive for other properties 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 errors 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 behaviour of the sensor.

 

 

Resolution

 

The resolution of a sensor is the smallest change it can detect in the quantity that it is measuring. Often in a digital display, the least significant digit will fluctuate, indicating that changes of that magnitude are only just resolved. The resolution is related to the precision with which the measurement is made. For example, a scanning probe (a fine tip near a surface collects an electron tunneling current) can resolve atoms and molecules.

 

 

Biological

 

All living organisms contain biological sensors with functions similar to those of the mechanical devices described. Most of these are specialized cells that are sensitive to:

 

Light, motion, temperature, magnetic fields, gravity, humidity, vibration, pressure, electrical fields, sound, and other physical aspects of the external environment;

Physical aspects of the internal environment, such as stretch, motion of the organism, and position of appendages (proprioception);

an enormous array of environmental molecules, including toxins, nutrients, and pheromones;

Many aspects of the internal metabolic milieu, such as glucose level, oxygen level, or osmolality;

an equally varied range of internal signal molecules, such as hormones, neurotransmitters, and cytokines;

and even the differences between proteins of the organism itself and of the environment or alien creatures.

Artificial sensors that mimic biological sensors by using a biological sensitive component, are called biosensors.

 

Actuator

Data acquisition

Data acquisition system

Data logger

 Detection theory

Fully Automatic Time

Hydrogen microsensor

Lateral line

Limen

 List of sensors

Machine olfaction

Receiver operating characteristic

Sensor network

About the Author

Assistant professor in lord venkateswara engineering college.I am doing phd in sathyabama university, Tamil Nadu,India.

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