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SENSORS AND THEIR APPLICATIONS

PRESENTED BY MRINALNEHA SHRIVASTAVA

NIDHI.P.TIGGA

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TOPICS INCLUDED IN THIS PRESENTATION

INTRODUCTION OPTICAL SENSORS PRINCIPLE OF SENSORS CLASSIFICATION AND COMPARISON SOME INTERESTING APPLICATIONS CHRONOLOGYCONCLUSION

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SENSOR INTRODUCTION A sensor is a device that produces a measurable

response to a change in a physical condition, such as temperature or thermal conductivity, or to a change in chemical concentration. Sensors are particularly useful for making in-situ measurements such as in industrial process control.

Sensors are responsible for converting some type of physical phenomenon into a quantity measurable by a data acquisition (DAQ) system.

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OPTICAL SENSORINTRODUCTION

NEW REVOLUTION OF OPTICAL FIBER SENSORS

IT IS A “SPIN-OFF” FROM OTHER OPTICAL TECHNOLOGIES

SEEING THE POTENTIAL IN SENSING APPLICATIONS – DEVELOPED AS ITS OWN FIELD

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TEMPERATURE CHEMICAL SPECIES

PRESSURE FORCE

FLOW RADIATION

LIQUID LEVEL pH

DISPLACEMENT HUMIDITY

VIBRATION STRAIN

ROTATION VELOCITY

MAGNETIC FIELDS

ELECTRIC FIELDS

ACCELERATION ACOUSTIC FIELDS

OPTICAL SENSOR MEASURANDS

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WORKING PRINCIPLE

                                                                               

• LIGHT BEAM CHANGES BY THE PHENOMENA THAT IS BEING MEASURED

• LIGHT MAY CHANGE IN ITS FIVE OPTICAL PROPERTIES i.e INTENSITY, PHASE, POLARIZATION,WAVELENGTH AND SPECTRAL DISTRIBUTION  

CLASSIFICATION

OPTICAL SENSORS ARE OF

EXTRINSIC SENSORS

INTRINSIC SENSORS

TWO TYPES

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EXTRINSIC SENSORS

WHERE THE LIGHT LEAVES THE FEED ORTRANSMITTING FIBER TO BE CHANGED BEFORE IT CONTINUES TO THE DETECTOR BY MEANS OF THE RETURN OR RECEIVING FIBER 

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INTRINSIC SENSORS

INTRINSIC SENSORS ARE DIFFERENT IN  THAT THE LIGHT BEAM DOES NOT LEAVE THE OPTICAL FIBERBUT IS CHANGED WHILST STILL CONTAINED WITHIN IT. 

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COMPARISON OF THE TWO TYPES EXTRINSIC INTRINSIC

APPLICATIONS- TEMPERATURE, PRESSURE,LIQUID LEVEL AND FLOW.

LESS SENSITIVE EASILY MULTIPLEXED INGRESS/ EGRESS CONNECTION PROBLEMS EASIER TO USE LESS EXPENSIVE

APPLICATIONS- ROTATION, ACCELERATION, STRAIN, ACOUSTIC PRESSURE AND VIBRATION.MORE SENSITIVE TOUGHER TO MULTIPLEXREDUCES CONNECTION PROBLEMSMORE ELABORATE SIGNAL DEMODULATIONMORE EXPENSIVE

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Types of Optical Sensors

Chemical/Gas Concentration Temperature Strain Biomedical Electric & Magnetic Fields Rotation Pressure Displacement &Position

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CHEMICAL SENSORS

REMOTE SPECTROSCOPY GROUNDWATER AND SOIL

CONTAMINATION MAJOR PLAYERS IN CHEMICAL SENSORS

1) PHARMACIA BIOTECH (SWEDEN)

2) FIBERCHEM

3) THE QUANTUM GROUP

Chemical/Gas Sensor Types and Applications.

Sensor type

Detectable gases

Usable range Pro's

Con's

Electrochemical Toxics, oxygen ppm levelsLow power, accurate, repeatable

3 year lifetime slightly lower at high temps; some types are cross-sensitive

Pellistor Flammables LEL levelsGenerally good in all ways; portable

Can be damaged by high levels of H2S, but poison resistant types are available

Infrared Flammables and CO20.1 (or less) to 100% by volume

Fail safe; generally excellent

Expensive (but getting cheaper); non-portable

Thermal Conductivity

Many, at % levels, including binary mixtures

% levels20 year life (at least); stable; can detect inert gases

Only appropriate for certain gases

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TEMPERATURE SENSORS

LARGEST COMMERCIALLY AVAILABLE SENSORS

RANGE -40 deg C TO 1000 deg C

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TYPES OF TEMPERATURE SENSORS

ThermocouplesThermistorsRadiation PyrometerRadiation ThermometersResistance Temperature DetectorsFiber Optic Temperature SensorsSilicon Temperature Sensors

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APPLICATIONS HVAC - room, duct, and refrigerant

equipment Motors - overload protection Electronic circuits - semiconductor protection Electronic assemblies - thermal management,

temperature compensation Process control - temperature regulation Automotive - air and oil temperature Appliances - heating and cooling temperature

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STRAIN SENSORS FIBER BRAGG GRATINGS (FBG)

TECHNOLOGY SENSES AS LITTLE AS 9

MICROSTRAIN NRL and UNITED TECHNOLOGY

RESEARCH

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BIOMEDICAL SENSORS

SPECTROSCOPIC BIOMEDICAL SENSORS

CO 2, O 2 and pH CAN BE MEASURED SIMULTANEOUSLY

FLOW MONITORING BY LASER DOPPLERIMETRY

FIBERS – OPTHALMOLOGIC APPLICATION

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ELECTRICAL AND MAGNETIC SENSORS

APPEALING- INHERENT DIELECTRIC NATURE

LESS SENSITIVE TO ELECTROMAGNETIC INTERFERENCE

SMALL SIZE AND SAFER THEY ARE ALMOST ALWAYS HYBRIDABB CORPORATION RESEARCH

CENTER

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APPLICATIONCompassing and navigationVehicle Detection Virtual RealityLaboratory Instrumentationa Medical InstrumentsUnderground Boring EquipmentFlux Gate Replacement

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ROTATION SENSOR

BASED ON THE SAGNAC EFFECTTWO TYPES RING LASER

GYROSCOPE (RLG) AND FIBER OPTIC GYROSCOPE (FOG)

US COMPANIES PURSUING HIGH PERFORMANCE FOG’s (HONEYWELL, LITTON, NORTHRUP, ALLIED SIGNAL etc.)

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PRESSURE SENSORS EARLIER BASED ON

PIEZORESISTIVE TECHNIQUEBASED ON MOVABLE DIAPHRAGMHIGH PERFORMANCE-

(POLARIZATION BASED SENSORS) OPERATING PRESSURE RANGES

FROM 0-70,000 torr

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DISPLACEMENT AND POSITION SENSORS ONE OF THE FIRST OPTOELECTRONIC

SENSORS TO BE DEVELOPED.SIMPLE SENSORS RELY ON THE

CHANGE IN RETROREFLECTANCE DUE TO A PROXIMAL MIRROR SURFACE

ALSO REFERRED AS LIQUID LEVEL SENSORS

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WHY OPTICAL SENSORSELECTROMAGNETIC IMMUNITY ELECTRICAL ISOLATION COMPACT AND LIGHT BOTH POINT AND DISTRIBUTED

CONFIGURATION WIDE DYNAMIC RANGE AMENABLE TO MULTIPLEXING

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APPLICATIONS

MILITARY AND LAW ENFORCEMENT

THIS SENSOR ENABLES LOW LIGHT IMAGING AT TV FRAME RATES AND ABOVE WITHOUT THE LIMITATIONS OF VACUM TUBE BASED SYSTEMS. 

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NIGHT VISION CAMERA (contd.)COMPRISES OF : AMPLIFIED CCD SENSOR ANTI BLOOMING TECHNOLOGY CRYSTAL POLYMER SHUTTER

ADVANTAGES : EXCEPTIONAL DAY LIGHT RESOLN. IMMUNE TO OVER EXPOSURE VERY HIGH CONTARAST LEVELS NO HALOING OR SCINTILLATIONS

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BIOMETRICS YOUR FACE, FINGERS AND EYES IN A WHOLE

NEW LIGHT

• IMAGE CAPTURE • IMAGE PROCESSING• FEATURE EXTRACTION • FEATURE COMPARISON 

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PARTIAL DISCHARGE DETECTION

USES OPTICAL FIBER SENSORS OPTICAL FIBER SENSORS ARE BEING TESTED FOR USE IN DETECTING PARTIAL DISCHARGES IN ELECTRICAL TRANSFORMERS. PINPOINTING SUCH DISCHARGES IS ESSENTIAL TO PREVENTING INSULATION BREAKDOWN AND CATASTROPHIC FAILURES. 

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CONCLUSIONS LOOKING AT THE INDUSTRY

TRENDS IN THE PAST 2 DECADES AND THE EXPONENTIAL CURVE IT SEEMS TO ME THAT THERE IS GOING TO BE A LOT OF RESEARCH AND IMPROVEMENTS TO THE EXISTING SENSORS

OPTICAL SENSORS ARE HERE TO STAY !!!!

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THANK YOU FOR YOUR PATIENCE AND TIME

QUESTIONS ??