Pyroelectric sensors for the security Pyroelectric sensors for the security system applicationsystem application

Instructor:Instructor: Dr. Mohan Krishnan Dr. Mohan Krishnan

Team Members:Team Members: Chun-Chin You Chun-Chin You Kazi ahmedKazi ahmed

December 8, 2005December 8, 2005

IntroductionIntroduction

Overview of The Infrared Radiation Overview of The Infrared Radiation The Pyroelectric SensorThe Pyroelectric Sensor

What is the Pyroelectric Sensor ?What is the Pyroelectric Sensor ? How the Pyroelectric sensor work ?How the Pyroelectric sensor work ?

Project DescriptionProject Description Actual SetupActual Setup LimitationsLimitations ResultsResults Questions ?Questions ?

TheThe InfraredInfrared RadiationRadiation

Infrared radiation wavelength is longer than Infrared radiation wavelength is longer than visible light. visible light.

Objects generate heat and also generate Objects generate heat and also generate infrared radiation.infrared radiation.

objects include animals and the human body objects include animals and the human body whose radiation is strongest at a wavelength of whose radiation is strongest at a wavelength of 9.4um9.4um..

The Pyroelectric SensorThe Pyroelectric Sensor

What is the Pyroelectric Sensor ?What is the Pyroelectric Sensor ? The Pyroelectric sensor is made of a The Pyroelectric sensor is made of a

crystalline materialcrystalline material

The amount of radiation striking the crystal The amount of radiation striking the crystal changes, the amount of charge also changes, the amount of charge also changes.changes.

Typical crystalline materialTypical crystalline material– Terbium Gallium Garnet (TGG)Terbium Gallium Garnet (TGG)– lead titanate zirconate (PZT)lead titanate zirconate (PZT)

The PyroelectricThe Pyroelectric SensorSensor

Microstructures of Microstructures of

mixed PZT/aluminamixed PZT/alumina

The Pyroelectric SensorThe Pyroelectric Sensor

How the Pyroelectric sensor work ?How the Pyroelectric sensor work ?

Work theoryWork theory – The pyroelectric sensor has two sensing The pyroelectric sensor has two sensing

elements. elements.

The Pyroelectric SensorThe Pyroelectric Sensor - Our sensor ( - Our sensor ( IR 442)IR 442)

– The PyroelectricThe Pyroelectric SensorSensor

-The output signal -The output signal waveform shows that waveform shows that first a positive,first a positive,

-then zero and then a -then zero and then a negative transition negative transition resultsresults

The PyroelectricThe Pyroelectric Sensor Sensor - Our sensor ( - Our sensor ( IR 442)IR 442)

The PyroelectricThe Pyroelectric SensorSensor

– The Fresnel lens is made of an infrared The Fresnel lens is made of an infrared transmitting material transmitting material

Focusing deviceFocusing device

Project descriptionProject description

Overview of the system Overview of the system

Use the pyroelectric Use the pyroelectric sensor IR 442 servo, sensor IR 442 servo,

and web cam to build and web cam to build the security systemthe security system..

Project descriptionProject description

System SchematicSystem Schematic

Servo1 moves, Sensor scans

startRecord the data Servo2 indicates

the max value and holds the position Max

value

Servo1 and sensor go back to

start but no recording data

Actual SetupActual Setup

LimitationsLimitations

Don’t let the sensor face to the sun.Don’t let the sensor face to the sun.

Don’t let the sensor close the high heat source. Don’t let the sensor close the high heat source.

The scan distance of the detection of the sensor The scan distance of the detection of the sensor isis about 4.5m in our project .about 4.5m in our project .

Results (how did it work?)Results (how did it work?)

See !See !

Questions ?Questions ?

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