ECE5320 Mechatronics
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Prepared by: Jonathan Tran Dept. of Electrical and Computer Engineering Utah State University PowerPoint PPT Presentation


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ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Topic: Passive Infrared Sensor. Prepared by: Jonathan Tran Dept. of Electrical and Computer Engineering Utah State University E: [email protected] F: (435)797-3054 (ECE Dept.). 3/11/2010. Outline.

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Prepared by: Jonathan Tran Dept. of Electrical and Computer Engineering Utah State University

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Prepared by jonathan tran dept of electrical and computer engineering utah state university

ECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Topic: Passive Infrared Sensor

Prepared by:

Jonathan Tran

Dept. of Electrical and Computer Engineering

Utah State University

E: [email protected]

F: (435)797-3054 (ECE Dept.)

3/11/2010


Outline

Outline

  • Reference List

  • To Probe Further

  • What is a Passive Infrared Sensor?

  • Major Applications

  • Practical Applications

  • How It Works

  • Physical Appearance

  • Major Specifications

  • Limitations

  • Cost

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Reference list

Reference List

  • http://www.ladyada.net/learn/sensors/pir.html

  • http://www.glolab.com/pirparts/infrared.html

  • http://itp.nyu.edu/physcomp/sensors/Reports/PassiveInfraRedSensor

  • http://www.reuk.co.uk/PIR-Sensors.htm

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


To explore further survival pointers of web references etc

To Explore Further (survival pointers of web references etc)

  • http://en.wikipedia.org/wiki/Passive_infrared_sensor

  • http://www.ladyada.net/learn/sensors/pir.html

  • http://www.gadgetshack.com/motionsensor.html

  • http://en.wikipedia.org/wiki/Fresnel_lens

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


What is a passive infrared pir sensor

What is a Passive Infrared (PIR) Sensor?

  • Used to detect motion

  • Basically made up of pyroelectric sensors

    • Detect levels of infrared radiation

  • Does not emit any radiation, only detects, hence passive

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Major applications

Major applications

  • Motion Detection

    • Lighting Systems

    • Security Systems

    • Automation (doors, air conditioning, etc.)

  • Measuring Temperature Differentials

    • Measure temperatures of remote objects

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Practical applications

Practical Applications

  • Automatic doors

  • Interactive Rooms

    • Activate when person enters room

  • Remote triggered cameras

    • Take photos/start recording when person enters room

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


How it works theory

How It Works – Theory

  • Infrared radiation exists in the EM spectrum

    • Can’t be seen, but can be detected

  • Objects that generate heat also generate IR radiation

  • PIR sensor consists of two sensing elements

    • One gives a frame of reference and the other detects the change

    • Can only detect the difference in temperatures between the two sensors

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


How it works theory cont

How It Works – Theory (cont.)

  • For example: A PIR sensor is pointed into a room. An animal, with a temperature greater than the wall, walks into the room. As the animal crosses the first sensor, a positive pulse is produced. When the animal is in front of both sensors, there is no sensed change. As it crosses the second sensor, a negative pulse is emitted. These pulses are what is detected.

  • An illustration of this example is shown on the next slide

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


How it works theory cont1

How It Works – Theory (cont.)

http://www.glolab.com/pirparts/infrared.html

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


How it works fresnel lens

How It Works – Fresnel Lens

  • Captures more IR radiation

  • Focuses the radiation into a smaller point

  • Condenses the light and provides a larger range of IR to the sensor

http://www.ladyada.net/learn/sensors/pir.html

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


How it works fresnel lens cont

How It Works – Fresnel Lens (cont.)

  • Focal point moves across the sensor as the IR source moves, exposing one element at a time

  • Grooved side usually face the PIR sensor

http://www.ladyada.net/learn/sensors/pir.html

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


How it works fresnel lens cont1

How It Works – Fresnel Lens (cont.)

  • A Plano Convex lens that has been collapsed on itself to form a flat lens

  • Much smaller in thickness, so less absorption loss

http://www.glolab.com/pirparts/infrared.html

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


How it works fresnel lens cont2

How It Works – Fresnel Lens (cont.)

  • Usually thin and flexible

    • About 0.015 inches thick

  • Made of material opaque to visible light

    • Materials that pass visible light will not pass infrared radiation (e.g. glass, plastic, etc.)

http://www.ladyada.net/learn/sensors/pir.html

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


How it works summary

How It Works – Summary

  • Fresnel lens directs IR radiation at two pyroelectric sensors

  • Impulse gives the difference in temperature between two sensors

  • Motion is detected when a body with different temperature than the surroundings enters the frame of the sensor

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Physical appearance housing

Physical Appearance – Housing

  • Housed in a sealed metal can to improve noise/temp/humidity immunity

  • Three pin output – Drain, gate, & source

http://www.ladyada.net/learn/sensors/pir.html

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Physical appearance sensor window

Physical Appearance – Sensor Window

  • Sensing elements can be seen through the IR window

http://itp.nyu.edu/physcomp/sensors/Reports/PassiveInfraRedSensor

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Major specifications

Major Specifications

  • Power requirements

  • Communication (Output)

    • Single bit high/low output

  • Dimensions

  • Operating Temperature

  • Range

  • Detection Angle

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Limitations

Limitations

  • Sensing can be confused

    • Motion too close to sensor

    • Motion is not passed through sensor one at a time

    • Cannot detect slow moving or stationary objects

    • Sensor is approached straight on

  • Limited range in most sensors

  • Temperature sensitive

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Typical cost where to buy

Typical Cost/Where to Buy

  • Typical cost is about $10.00 for complete module

  • Discounts are given if ordering in large quantities

  • http://www.parallax.com/Store/Sensors/ObjectDetection/tabid/176/CategoryID/36/List/0/Level/a/ProductID/83/Default.aspx?SortField=ProductName%2cProductName

  • http://www.hvwtech.com/products_view.asp?ProductID=270

  • http://www.futurlec.com/PIR_Sensors.shtml

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


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