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TRUE OCCUPANCY SENSORS

TRUE OCCUPANCY SENSORS. BY TERRY WEI CHENGYU ZHANG DEBOJIT NAYAK. INSPIRATION FOR OUR PROJECT. WHAT IS OUR PROJECT IS ABOUT. Automated detection of number of people in a room Automated control of lighting system within a room

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TRUE OCCUPANCY SENSORS

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  1. TRUE OCCUPANCY SENSORS BY TERRY WEI CHENGYU ZHANG DEBOJIT NAYAK

  2. INSPIRATION FOR OUR PROJECT

  3. WHAT IS OUR PROJECT IS ABOUT • Automated detection of number of people in a room • Automated control of lighting system within a room • Prototype for implementation in large scale office building and campus classrooms

  4. ADVANTAGES AND BENEFITS • Conserve energy sources • Reduce unnecessary costs • Computer monitoring system • Improve decision-making abilities • Such as lighting and temperature controls

  5. PRODUCT COMPONENTS • Passive Infrared Sensor (PIR) • Voltage Regulator • Peripheral Interface Controller (PIC) • Transmitter • Receiver • Computer Display (RS-232) • Relay

  6. Passive Infrared Sensor Data PIC Microcontroller Relays (Lighting System) RS-232 (PC) DESIGN IMPLEMENTATION Wireless Transmission

  7. OVERALL STRUCTURE Transmitter Counting sensor 1 Transmitter Counting sensor 2 Transmitter Motion sensor 1 Transmitter Motion sensor 2 Receiver1 Receiver2 3 Receiver3 4 Receiver4 1 2 All circuits are powered by 9V battery via a 5 V voltage regulator.

  8. PASSIVE INFRARED SENSORS • Passive Infrared Sensor: • Parallax Inc., 555-28027ND PIR Sensor • Features: • Output: Single Bit • Output Voltage (High): 3.2 Volts • Output Voltage (Low): 0.0 Volts • Operational Voltage: 3.3 Volts and 5.0 Volts • Current Drawn: < 100 mA • Sensitivity: • Range (Distance): Approximately 20 Feet • Range (Angle): 120°by 70° • Design: Responds to Sudden Changes • Calibration: • Requires ‘warm-up’ time due to settling time involved in ‘learning’ its environment • Time Required: 30 Seconds Figure 1. Image of Passive Infrared Sensor

  9. PASSIVE INFRARED SENSORS Figure 3. Output of Passive Infrared Sensor with Motion from Figure 2 Figure 2. Diagram Displaying How Passive Infrared Sensor Detects Motion

  10. PASSIVE INFRARED SENSORS • Triggering time is extremely important • Detecting movement at 80 milliseconds (Triggering Time) • Too fast • Double detection – senses one person twice • Detecting movement at 3 seconds (Triggering Time) • Too slow • Multiple people will enter or exit without being detected • Optimal detection time is approximately one second (Triggering Time) • Various tests on timing how long it takes for a person to pass through the sensing system

  11. EXPLAINATION OF TRIGGERING TIME • TX = Triggering Time (Default Value: 3.4 second) • TX = 24576 * R10 * C6 • R10 = Resistor Value (Default Value: 200 kΩ) – Variable Value • C6 = Capacitance Value (Default Value: 0.24 nF) – Fixed Value • If TX is desired to be one second • New R10 Value is 30 kΩ • Resistor on sensor falls off when repeatedly changing triggering time, which causes sensor to be destroyed

  12. PASSIVE INFRARED SENSORS • Output from Oscilloscope: Default 200kΩ Resistor

  13. PASSIVE INFRARED SENSORS • Output from Oscilloscope: Attached 900Ω Resistor

  14. VOLTAGE REGULATOR • Voltage Regulator: • National Semiconductor LM78M05CT • 3 Terminal Positive Voltage Regulator • Features: • Output Current: Excess of 0.5 A • Output Voltage: 5 Volts • Internal thermal overload protection • Peak Current Output: 700 mA

  15. VOLTAGE REGULATOR • Schematic: 9V 5V 10 uF 1 uF Capacitor values were chosen to reduce ripple voltages – the larger the capacitance the better.

  16. 9-Volt Battery Input Voltage Regulator Passive Infrared Sensors LINX Transmitter Output Voltage (5 Volts) Output Voltage (5 Volts) Sensor Data VOLTAGE REGULATOR • Block Diagram:

  17. RF MODULE (TRANSMITTER) Used Four Different Frequencies for Each of the PIR Sensors Source: Project 9 Presentation

  18. RF MODULE (RECEIVER) Used Four Different Frequencies for Each of the PIR Sensors Source: Project 9 Presentation

  19. RF MODULE Testing RF Module Transmitter Input: Sine Wave Receiver Output: Square Wave (Indicating 1 and 0 or High and Low)

  20. RF MODULE Testing RF Module Transmitter Input: Signal from PIR Sensor Receiver Output: Delayed Reception

  21. RS-232 (PC CONNECTION) • MAX232 • Converts signal from RS-232 serial port to signal suitable for using in the microchip

  22. RS-232 (PC CONNECTION) • RS-232 • Cable Connection • C++ Application • Created using standard Windows libraries

  23. MICROCONTROLLER (counting) PIR1 on? PIR1 on? NO NO YES YES PIR2 on? PIR2 on? NO NO BOTH on? BOTH on? IN/OUT? +1&PIR off -1&PIR off

  24. MICROCONTROLLER (motion) Lights off in 20s PIR3 on? Lights on Lights off in 20s & Blink for 5s before turn off NO NO YES YES PIR4 on? NO NO YES YES Counter >0? Counter >0?

  25. RELAYS Small size for high density PC board mounting Ideal for appliance, office equipment. PIC Output

  26. PROJECT CONSTRUCTION (COUNTING SYSTEM)

  27. PROJECT CONSTRUCTION (ROOM SENSOR PRINTED CIRCUIT BOARD)

  28. PROJECT CONSTRUCTION (MAIN PRINTED CIRCUIT BOARD)

  29. ADDITIONAL FUNCTIONAL TESTS • Displaying Count Results

  30. ADDITIONAL FUNCTIONAL TESTS • Ultrasonic Sensor Testing Time = 1.160 ms Distance from sensor to object = 20 cm

  31. ADDITIONAL FUNCTIONAL TESTS • Ultrasonic Sensor Testing Time = 4.240 ms Distance from sensor to object = 73 cm

  32. ADDITIONAL FUNCTIONAL TESTS • Ultrasonic Sensors • Not used due to limitation of range of detection (4 meters) • Can be easily ignored if something is in the way of ultrasonic sensor

  33. SPECIAL SCENARIOS • Student hides under the table (or falls asleep) • Blinking system • Person enters in half way and decides to leave (or exits) • Causes false triggering of some entering • Carrying cardboard over one’s head • No detection or sensing • Bird enters room • Triggers room lights on • Throwing a hot dog into the room • Causes counting system to count

  34. SPECIAL SCENARIOS • If count is zero and movement in room • Triggers room lights on • Turning on lights and counting system are independent • Turning off lights and counting system are dependent (blinking) • Fan blowing air • Does not detect or sense • Material of clothes • Still sense people walking in and out

  35. SUCCESSES • PIC integration with passive infrared sensors • Receiving data from passive infrared sensors • Robust wireless transmission between passive infrared sensors and PIC • PIC analysis of passive infrared sensors to accurately keep count of number of people in room • PIC integration with RS-232 system • Data is correctly displayed on the PC • PIC integration with relays • Correctly controls the lighting system of the room based on sensor outputs

  36. CHALLENGES • PIC programming • Learning to program PIC and interrupts • Integrating and communicating data between PIC and RS-232 (PC) • Understanding how to receive data on PC • Integrating counting system with room sensors • Finding a logical connection between two systems • Accounting for extreme situations (particular cases) • Explained on previous slides • Designing printed circuit boards • Learning to use the Eagle Layout Editor • Soldering

  37. RECOMMENDATIONS (NEXT STEPS) • Use one receiver and sweep the desired frequencies to reduce hardware • Improve algorithm to integrate counting system with the room sensors • Add more sensors to enable a more robust algorithm for room detection and counting system • Implement the system on a full scale classroom with multiple quadrants • Integrate ultrasonic sensors with passive infrared sensors

  38. CREDITS • Professor: Professor Carney • Teaching Assistant: Paul Rancouret • Teaching Assistant: Kieran Levin • Teaching Assistant: Jay Rappert • PCB Production: Mark Smart • Door Overhead Design: ECE Machine Shop • Essential Hardware: ECE Parts Shop

  39. FURTHER QUESTIONS

  40. FUTURISTIC (POSSIBLE) DESIGNS

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