different type of sensor

1. 1
Physical Principles ofPhysical Principles of
SensingSensing
SOPHOMORE CLINIC ISOPHOMORE CLINIC I
FALL 2004FALL 2004

2. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 22
DefinitionDefinition
 A sensor is a device that receives a stimulus andA sensor is a device that receives a stimulus and
responds with an electrical signal.responds with an electrical signal.
Fig 1.1
Level control system. A sight tube and the
operator’s eye form a sensor.

3. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 33
What are some quantitiesWhat are some quantities
that can be sensed?that can be sensed?
 Motion, position,Motion, position,
displacementdisplacement
 Velocity andVelocity and
accelerationacceleration
 Force, strainForce, strain
 PressurePressure
 FlowFlow
 SoundSound
 MoistureMoisture
 LightLight
 RadiationRadiation
 TemperatureTemperature
 Chemical presenceChemical presence
These quantities are the stimulus.

4. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 44
Any sensor is an energy converterAny sensor is an energy converter
 This conversion can be direct or it mayThis conversion can be direct or it may
require transducers.require transducers.
 Example:Example:
• A chemical sensor may have a part whichA chemical sensor may have a part which
converts the energy of a chemical reaction intoconverts the energy of a chemical reaction into
heat (transducer) and another part, aheat (transducer) and another part, a
thermopile, which converts heat into anthermopile, which converts heat into an
electrical signal.electrical signal.
Fig 1.2

5. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 55
Physical Principles of SensingPhysical Principles of Sensing
 Charges, fields &Charges, fields &
potentialspotentials
 CapacitanceCapacitance
 MagnetismMagnetism
 InductionInduction
 ResistanceResistance
 Piezoelectric effectPiezoelectric effect
 Seebeck andSeebeck and
Peltier effectsPeltier effects
 Thermal propertiesThermal properties
of materialsof materials
 Heat transferHeat transfer
 LightLight

6. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 66
The Response is anThe Response is an
Electrical SignalElectrical Signal
 When we say electrical weWhen we say electrical we
mean a signal which canmean a signal which can
be channeled, amplifiedbe channeled, amplified
and modified by electronicand modified by electronic
devices:devices:
• VoltageVoltage
• CurrentCurrent
• ChargeCharge
 The voltage, current orThe voltage, current or
charge may be describecharge may be describe
by:by:
• AmplitudeAmplitude
• FrequencyFrequency
• PhasePhase
• Digital codeDigital code

7. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 77
PIR SensorPIR Sensor

8. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 88

9. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 99
Gas SensorGas Sensor

10. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1010
ModuleModule

11. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1111
Rain SensorRain Sensor

12. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1212
Alcohol SensorAlcohol Sensor

13. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1313
Continue…Continue…

14. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1414
Touch SensorTouch Sensor

15. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1515
Continue….Continue….

16. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1616
Color SensorColor Sensor

17. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1717
GyroscopeGyroscope

18. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1818
Continue…Continue…

19. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 1919
Ultrasonic SensorUltrasonic Sensor

20. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 2020
Continue…Continue…

21. Video of Top 5 ProjectsVideo of Top 5 Projects
FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 2121

22. Top 5 Solar ProjectsTop 5 Solar Projects
FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 2222

23. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 2323
ConclusionsConclusions
 A sensor is a device that receives aA sensor is a device that receives a
stimulus and responds with anstimulus and responds with an
electrical signal.electrical signal.
 The final stage of any sensor isThe final stage of any sensor is
dependent upon the electricaldependent upon the electrical
properties of the sensor materials.properties of the sensor materials.
 The materials introduced today areThe materials introduced today are
used in the design and fabrication ofused in the design and fabrication of
many different types of sensors.many different types of sensors.

24. MotivationalMotivational
FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 2424

25. FALL 2004FALL 2004 SOPHOMORE CLINICSOPHOMORE CLINIC 2525
Thank YouThank You