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Unobtrusive Directional Occupancy Counter. William Case Neeraj Chemburkar Christopher Cody Team 39, TA: Drew Handler. Objectives. Develop product to determine classroom occupancy Cost effective solution Unobtrusive Low power Low maintenance Easy installation
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Unobtrusive Directional Occupancy Counter William Case NeerajChemburkar Christopher Cody Team 39, TA: Drew Handler
Objectives • Develop product to determine classroom occupancy • Cost effective solution • Unobtrusive • Low power • Low maintenance • Easy installation • Support for multiple doors • 90% accuracy
Power Supplies Sensor Board • 9V battery source • Voltage regulators • 5VDC and 3.3VDC Base Station • Wall-wart supply • output 5VDC and 3.3VDC
PIR Sensor Dual Type Pyroelectric Infrared Sensor IRA-E700 Series schematic
Sensor Interface PIR
Correct Measured Output T_OUT D_OUT
Incorrect Measured Output T_OUT D_OUT
Results Pros Cons Random third spike Radial Sensing • Able to bi-directionally detect motion • One sensor per door • Long range of sensing • Able to output clear digital waveforms • according to direction
Microcontrollers Texas Instruments MSP430G2553 Multiple low power modes 16 GPIO pins Built in UART, timer peripherals
Sensor Board Controller Functions Sensing algorithm Wait for pulse from D_OUT Check value of T_OUT shortly after first pulse Wait for T_OUT transition and evaluate direction • Interprets outputs from sensors • Stores temporary count and channel identifier • Sends count to transmitter • Change channels on button inputs
Base Station Controller • Interprets incoming data from receiver • Only accepts data on the correct channel • Stores total room count • Sends count to WiFi module over UART
RF Modules • Sparkfun 434 MHz transmitter and receiver • Usable package • Up to 500 ft. range
Transmission Scheme • Avoid corruption from noise • Easily interpretable • Low pulse followed by: • Short high = “1” • Long high = “0”
Measured Transmission Output CHANNEL DATA START “6”0110 “08”0000 1000 “A”1010 “F”1111
WizFi210 WiFi module • UART • Enterprise Connectivity • Auto-reconnect to network • IP address identification • Potential use for CITES • Example Information • “Count: 43”
Power Saving • Single PIR • Separation of modules • Enable bit for transmitter • MCU • Interrupt function • Low power mode • Display control
Future Improvements • Testing more/different PIR sensors • Custom fresnel lens • Two individual PIRs per sensor board • Stronger detection algorithm • One base station for multiple rooms • Two-way communication with the base station and CITES