A Pyroelectric Infrared Sensor


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A Pyroelectric Infrared Sensor

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