A Pyroelectric Infrared Sensor
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A Pyroelectric Infrared Sensor






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A Pyroelectric Infrared Sensor Presentation Transcript

  • 1. A Pyroelectric Infrared Sensor-based Indoor Location-Aware System for the Smart Home 指導老師 : 張耀仁 學生 : 莊育嘉
  • 2. Reference
    • S Lee, KN Ha, KC Lee - Consumer Electronics, IEEE Transactions on, 2006 - ieeexplore.ieee.org
  • 3. Outline
    • Abstract
    • Introduction
    • Architecture of the PILAS ( PIR Sensor-Based Indoor Location-Aware System)
    • Performance evaluation of the PILAS
    • Summary and conclusions
  • 4. Abstract
    • Key issue of smart home
      • how to detect the locations of resident
    • Two approaches of research effort
      • Terminal-based
        • Resident must carry a type of device
      • Non-terminal-based
        • Resident don’t carry such device
    • This paper use non-terminal-based approach
      • Pyroelectric infrared sensors( PIR sensors)
  • 5. Introduction
    • How to enhance a resident’s convenience and safety
      • multimedia appliance
      • Internet appliances were connected via a home network system
      • Controlled or monitored remotely using a TV or PDA
      • Location-based service
        • Can anticipate the resident
        • Offer appropriate intelligent service
  • 6. Introduction (continued)
    • According to the measurement technology, indoor location-aware system have been classified into three types
      • Triangulation
      • Scene analysis
      • Proximity methods
  • 7. Triangulation
    • This method uses multiple distances from multiple known points.
    • Example
      • Active Badges
        • Use infrared sensors
      • Active Bats
        • Use ultrasonic sensors
      • Easy Living
        • Use vision sensors
  • 8. Scene analysis
    • The Scene analysis method examines a view from a particular vantage point.
    • Examples
      • MotionStar
        • Use a DC magnetic tracker
      • RADAR
        • Use IEEE 802.11 local area network (LAN)
  • 9. Proximity methods
    • The proximity methods measures nearness to a known set of points.
    • Example
      • Smart Floor
        • Uses pressure sensors
  • 10. Introduction (continued)
    • According to the need for terminal should be carried by the resident, indoor location-aware system have been classified into two types.
      • Terminal-based method
      • Non-terminal method
  • 11. Terminal-based methods
    • Active Bats
      • Use RFID tag
      • Use infrared transceiver
      • It is impossible to recognize the resident’s location when user didn’t carry such devices.
  • 12. Non-terminal methods
    • This method can find resident’s location without such devices
    • Easy Living
      • Be regarded to invade the resident’s privacy
    • Smart Floor
      • This method has difficulty with extendibility and maintenance
  • 13. Introduction (continued)
    • This paper presents a non-terminal based location-aware system
    • Use pyroelectric infrared (PIR) sensors
      • Detection areas of adjacent
      • sensors overlap
      • Locate a resident
        • Combining the outputs of
        • multiple PIR sensors,
  • 14. Architecture of the PILAS
    • Framework of the smart home
    • Location-recognition algorithm
  • 15. Framework of the smart home
    • An indoor location-aware system must satisfy the following requirements
      • Location-aware system should be implemented relatively low cost
      • Sensor installation must be flexible
      • Sensors have to be robust to noise
      • Sensors should not be affected by their surroundings
      • It is desirable that the system’s accuracy is adjustable according to room types
  • 16. Advantage of PIR sensors
    • Have been used to turn on a light when it detects human movements
    • Less expensive
    • Robust to surroundings
      • Infrared detect wavelength between 9.4~10.4μm
      • In terms of temperature, humidity, electromagnetic noise
    • Possible to control the accuracy
    • Easily installed on the ceiling
  • 17. Framework of the smart home( continue)
    • Device are connected via a home network
      • PIR sensors
      • Room terminals
      • Smart home server
      • Home appliances
    • Each room is a cell
    • Each PIR sensor
    • detect the resident
    • at a constant period
  • 18. Functions in smart home server
    • Generating a virtual map
    • Writing the resident’s movement
    • Provide intelligence services
      • Via the home network
    • Save the current information
      • Movement trajectory of the resident
      • Current action of home appliance
      • Current home environment
    • May offer human-oriented intelligent services
  • 19. Location-recognition algorithm
    • In Fig. 3, Resident in 1
      • a output ‘ON’, b and c outputs ‘OFF’
    • In Fig. 3, Resident in 2
      • a and b output ‘ON’, c outputs ‘OFF’
    • If three or more sensors signal ‘ON’, the resident is located at the centroid of the centers
  • 20. Location-recognition algorithm( continue )
    • The accuracy of this system is adjustable.
      • In Figure.3, the radius of the sensing area is1m, then the maximum error is 1m.
      • When resident is at point 2, the maximum error is √3/2
      • m
  • 21. More sensing areas will increase the accuracy of the system
    • Fig. 4. Location accuracy according to the sensor arrangement of PIR sensors. (a) 40 sensing areas. (b) 21 sensing areas. (c) 28 sensing areas with twelve sensors.
  • 22. Sensors on the edges must to be located a little inwards
    • Fig. 5. The effect of compensating for the center point of the outer sensors. (a) Resident’s movement. (b) Before compensating for the outer sensors. (c) After compensating for the outer sensors.
  • 23. Performance evaluation of the PILAS
    • Resident-detection method using PIR sensors
      • The requirements of resident-detection method
      • Implementation method for the resident-detection method for PIR sensors
    • Performance evaluation using an experimental test bed
  • 24. Resident-detection method using PIR sensors
    • Recognize the resident’s location by combining outputs from all the sensors belonging to one cell
      • Every sensor’s state will influence location accuracy
      • the ‘ON’/’OF’ values can be determined by comparing a predefined threshold and the digitized sensor output acquired by sampling the analog signal from a PIR sensor
      • It’s important to find appropriate threshold
  • 25. Signal output of PIR sensor Resident enters a sensing area The variation in the Infrared radiation increase PIR sensor outputs an Increasing voltage
  • 26. The requirements of resident-detection method
    • PIR sensors must not malfunction by other disturbance
    • It should be possible to precisely determine the point in time, include resident’s speed and height.
    • It is necessary to know if a resident stays within the sensing area
  • 27. The resident -detection method for PIR sensors (continue)
    • Use Fresnel lens
      • Allows human waveforms to pass through it while reject other waveforms
      • To eliminate malfunctioning due to pets or temperature changes
    • Resident has entered a sensing area
      • Output of a PIR sensor exceeds the positive threshold voltage
      • This state maintained for several intervals
  • 28. The resident -detection method for PIR sensors (continue)
    • Threshold must be sufficient for the method
      • The method can distinguish variation between the resident’s infrared and other’s infrared
    • The resident has left
      • Sensor’s output falls below a negative threshold voltage
      • The status maintained for several sampling intervals
    • A resident stays within the sensing area
      • Output voltage remains between two threshold voltage
  • 29. Performance evaluation using an experimental test bed
    • Design the system have a location accuracy of 0.5 m
    • Room
      • 4×4×2.5 m
      • (width× length× height)
      • 12 PIR sensors fixed on
      • the ceiling
      • The method is
      • shown in Fig. 4(c)
  • 30. Performance evaluation using an experimental test bed (continue)
    • Signal processing and judging ‘ON/OFF’
      • Atmel AT89C51CC001 microcontroller
      • A Nippon Ceramic RE431B PIR sensor
      • NL-11 Fresnel lens
      • A horn was installed on each PIR sensor to limit the sensing area to the circle with 2 m diameter
  • 31. Performance evaluation using an experimental test bed (continue)
    • Fig. 8 shows the experimental results with the horn
      • In a, walk straight
      • line
      • In b, moves within
      • the circle
      • In c, moves outside
      • the circle
  • 32. Choose threshold
    • To judge the signal is ’ON’ or ‘OFF’
    • When the threshold of the RE431B was ‘ ‘
      • This value based on the the respect to the internal temperature change
      • External environmental temperature change didn’t affect its performance at detecting the resident
      • Pets didn’t affect the performance
  • 33. Determine the resident’s location
    • PC-based location recognition algorithm
      • Collected data every 10msec
      • Use an NI 6025E data acquisition (DAQ) board
    • In Fig. 9
      • It was drawn using a mouse in left window
      • On the right is the estimated movement trajectory of resident
  • 34. Determine the resident’s location
    • Fig. 9, moving along a T-shaped path
      • Trajectory made by connecting the resident’s location
      • recognized by the PILAS
      • Maximum location
      • error is about 30 cm
  • 35. Summary and conclusions
    • The location accuracy in this paper is lower than 0.5 m
    • It is possible to enhance the location accuracy of the system
    • This system should be extended to deal with a room occupied by more than one resident