1. SENSORS AND THEIR
APPLICATIONS
PRESENTED BY
MRINAL
NEHA SHRIVASTAVA
NIDHI.P.TIGGA
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2. TOPICS INCLUDED IN THIS
PRESENTATION
 INTRODUCTION
 OPTICAL
SENSORS
 PRINCIPLE OF SENSORS
 CLASSIFICATION AND COMPARISON
 SOME INTERESTING APPLICATIONS
 CHRONOLOGY
 CONCLUSION
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3. 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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4. OPTICAL SENSOR
INTRODUCTION
 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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5. OPTICAL SENSOR MEASURANDS
TEMPERATURE
CHEMICAL
SPECIES
PRESSURE
FORCE
FLOW
RADIATION
LIQUID LEVEL
pH
DISPLACEMENT HUMIDITY
VIBRATION
STRAIN
ROTATION
VELOCITY
MAGNETIC
FIELDS
ELECTRIC
FIELDS
ACCELERATION ACOUSTIC
FIELDS
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6. 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
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7. CLASSIFICATION
OPTICAL SENSORS ARE OF TWO TYPES

EXTRINSIC SENSORS

INTRINSIC SENSORS
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8. EXTRINSIC SENSORS
WHERE THE LIGHT LEAVES THE FEED OR
TRANSMITTING FIBER TO BE CHANGED BEFORE
IT CONTINUES TO THE DETECTOR BY MEANS
OF THE RETURN OR RECEIVING FIBER
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9. INTRINSIC SENSORS
INTRINSIC SENSORS ARE DIFFERENT IN THAT THE
LIGHT BEAM DOES NOT LEAVE THE OPTICAL FIBER
BUT IS CHANGED WHILST STILL CONTAINED WITHIN IT.
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10. COMPARISON OF THE TWO TYPES
EXTRINSIC
INTRINSIC
APPLICATIONS-
APPLICATIONS-
TEMPERATURE,
PRESSURE,LIQUID
LEVEL AND FLOW.
ROTATION,
ACCELERATION, STRAIN,
ACOUSTIC PRESSURE
AND VIBRATION.
MORE SENSITIVE
TOUGHER TO
MULTIPLEX
REDUCES CONNECTION
PROBLEMS
MORE ELABORATE
SIGNAL DEMODULATION
MORE EXPENSIVE
LESS
SENSITIVE
EASILY MULTIPLEXED
 INGRESS/ EGRESS
CONNECTION
PROBLEMS
EASIER TO USE
LESS EXPENSIVE
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11. Types of Optical Sensors
Chemical/Gas Concentration
 Temperature
 Strain
 Biomedical
 Electric & Magnetic Fields
 Rotation
 Pressure
 Displacement &Position

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12. CHEMICAL SENSORS



REMOTE SPECTROSCOPY
GROUNDWATER AND SOIL
CONTAMINATION
MAJOR PLAYERS IN CHEMICAL SENSORS
1) PHARMACIA BIOTECH (SWEDEN)
2) FIBERCHEM
3) THE QUANTUM GROUP
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13. Chemical/Gas Sensor Types and
Applications.
Sensor
type
Detectable
gases
Usable
range
Pro's
Con's
ppm levels
3 year lifetime
slightly lower at
Low power, accurate,
high temps; some
repeatable
types are crosssensitive
Flammables
LEL levels
Can be damaged by
Generally good in all high levels of H2S,
ways; portable
but poison resistant
types are available
Infrared
Flammables and CO2
0.1 (or less) to
100% by volume
Fail safe; generally
excellent
Thermal
Conductivity
Many, at % levels,
including binary
mixtures
% levels
20 year life (at least);
Only appropriate for
stable; can detect
certain gases
inert gases
Electrochemical
Pellistor
Toxics, oxygen
Expensive (but
getting cheaper);
non-portable
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14. TEMPERATURE SENSORS
LARGEST COMMERCIALLY
AVAILABLE SENSORS
 RANGE -40 deg C TO 1000 deg C

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15. TYPES OF TEMPERATURE
SENSORS
 Thermocouples
 Thermistors
 Radiation
Pyrometer
 Radiation Thermometers
 Resistance Temperature Detectors
 Fiber Optic Temperature Sensors
 Silicon Temperature Sensors
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16. 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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17. STRAIN SENSORS
 FIBER
BRAGG GRATINGS (FBG)
TECHNOLOGY
 SENSES AS LITTLE AS 9
MICROSTRAIN
 NRL and UNITED TECHNOLOGY
RESEARCH
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18. 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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19. ELECTRICAL AND MAGNETIC
SENSORS
 APPEALING-
INHERENT DIELECTRIC
NATURE
 LESS SENSITIVE TO
ELECTROMAGNETIC INTERFERENCE
 SMALL SIZE AND SAFER
 THEY ARE ALMOST ALWAYS HYBRID
 ABB CORPORATION RESEARCH
CENTER
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20. APPLICATION
 Compassing
and navigation
 Vehicle Detection
 Virtual Reality
 Laboratory Instrumentation
 a Medical Instruments
 Underground Boring Equipment
 Flux Gate Replacement
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21. ROTATION SENSOR
 BASED
ON THE SAGNAC EFFECT
 TWO 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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22. PRESSURE SENSORS
 EARLIER
BASED ON
PIEZORESISTIVE TECHNIQUE
 BASED ON MOVABLE DIAPHRAGM
 HIGH PERFORMANCE(POLARIZATION BASED SENSORS)
 OPERATING PRESSURE RANGES
FROM 0-70,000 torr
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23. 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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24. WHY OPTICAL SENSORS
 ELECTROMAGNETIC
IMMUNITY
 ELECTRICAL ISOLATION
 COMPACT AND LIGHT
 BOTH POINT AND DISTRIBUTED
CONFIGURATION
 WIDE DYNAMIC RANGE
 AMENABLE TO MULTIPLEXING
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25. 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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26. 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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27. BIOMETRICS
YOUR FACE, FINGERS AND EYES IN A WHOLE
NEW LIGHT
• IMAGE CAPTURE
• IMAGE PROCESSING
• FEATURE EXTRACTION
• FEATURE COMPARISON
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28. 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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29. 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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30. THANK YOU FOR YOUR
PATIENCE AND TIME
QUESTIONS ??
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