Outline • What are wireless sensor networks? Dragon Star Lecture • Applications Wireless Sensor Netw orks • Course organization Chenyang Lu Department of Computer Science & Engineering Washington University in St. Louis May 2008 2 Smart Dust Mica2 Mote • Processor + Sensors + Wireless Interface 128KB • Miniature hardware manufactured economically in large numbers 2 AA Instruction EEPROM 4KB Data EEPROM 512KB Chipcon External CC1000 radio, Atmel Flash 38K or 19K baud, ATmega128L μ P Memory UART 2 7.3827MHz 315, 433, or SPI bus 900MHz (16 bytes x 3 LEDs 32768 rows) ADC 0-7 UART 1 I2C Bus Smart Dust (UCB) To Sensors, JTAG, and/or 51 pin I/O Connector 3 Programming Board 4 MTS420 Sensor Board Imote2 • GPS • Intel PXA271 Xscale Processor • Accelerometer – 13-416MHz • Light – 32MB FLASH/32MB SDRAM • 802.15.4 Radio (2.4GHz) • Temperature • Humidity • Barometric Pressure • 2KB EEPROM Conf. 5 6 1
Habitat Monitoring Applications Redw ood Trees • Smart sensors Structural Health Inventory embedded in Monitoring Management environments • Wireless networking • Fine-grained Fire Monitoring Habitat Monitoring monitoring & control Modified from Deborah Estrin, SIGMETRICS keynote, 7 8 http://lecs.cs.ucla.edu/~estrin/talks/Sigmetrics-June02.ppt Source: David Culler’s MobiHoc’05 Keynote Habitat Monitoring Great Duck Island Tiered Architecture Great Duck Island Monitor • usage patterns of burrows • burrow and environmental changes • differences between nesting areas and others http://www.greatduckisland.net Source: IEEE Spectrum 9 10 Surveillance Great Duck Island Requirements Wireless Integrated Netw orked Sensors (WINS) • 9-month season � low power � low duty cycle • Reliability – Detection probability & false alarm rate • Handle hash environment • Energy efficiency – Verification network • Real-time – Health monitoring • Low cost • Solution: In-network processing in multi-tier network • Non-real-time, low data rate – 5-10 min: entry/leave – 2-4 hr: environmental differential • No in-network processing: data streaming 11 12 2
WINS Medical Care Tiered Architecture CodeBlue • Tiers – Low-power sensors provide continuous vigilance • Seismic, infared, sound – High-power sensors • Cameras – Human operators (most expensive!) Accelerometer, gyroscope, Wireless pulse Wireless two-lead EKG and electromyogram (EMG) • Phased execution oximeter sensor sensor for stroke patient Monitoring – Low tier activate higher tier when necessary – Stop as soon as certainty threshold is reached http://www.eecs.harvard.edu/~mdw/proj/codeblue/ Power efficiency & reliability 13 14 Structural Health Monitoring CodeBlue Golden Gate Bridge Requirements • Security & privacy • Reliability • Real-time – Detect sudden change in patient conditions • Mobility: Doctors, patients, equipments 15 16 Source: David Culler’s MobiHoc’05 Keynote Structural Monitoring Diverse Requirements • High sampling frequency • Requirements are highly application-dependent – A tri-axial accelerometer: 100 Hz sampling � 4.8 Kbps • Need to optimize design for specific applications • Reliable data transfer Real-time Security Reliability Energy • Time synchronization GDI None None None Very Low • Real-time: detect damage after earthquake WINS High High High Low CodeBlue High High High Medium GGB Medium None High Low 17 18 3
Global Sensing Summary: Applications Beyond a Single Sensor Netw ork • Wireless sensor networks have been deployed successfully in the real world. • Tiered architecture is common Ship Train – Sensing, communication • Diverse, application-specific challenges – Energy, management, mobility, real-time, reliability, security, privacy…… Truck Customer, Shipper, DHS, CBP Shipping Yard 19 20 Topics Pointers • http://www.cs.wustl.edu/~lu/ds08.html • Feel free to ask questions and discuss! Date AM ( 10- 12) PM ( 1:30- 3:30) 5/ 26 Int roduct ion Operat ing Syst em 5/ 27 Programming Middleware 5/ 28 Media Access Cont rol MAC Layer Archit ect ure 5/ 29 Minimum Power Configurat ion Coverage & Connect ivit y 5/ 30 Query Scheduling Mobile Query 21 22 4
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