Wireless Sensor Networks for Habitat Monitoring

1. Wireless Sensor Networksfor Habitat Monitoring Alan Mainwaring, Joseph Polastre, Robert Szewczyk, and David Culler Intel Research Lab. / UCBerkely Seo, Dong Mahn

2. Contents • Introduction • Application Requirements • System Architecture • Design and Implementation Strategies • Sensor Network Services • Current Progress • Additional materials • Conclusion

3. Introduction • Habitat and environmental monitoring • Technical interests in these applications • developing an appropriate sensor network architecture • simple, concrete solutions • application-driven approach • actual problems from potential ones • relevant issues from irrelevant ones • collaboration with scientists in other fields

4. Introduction (cont.) • Instrumentation of natural spaces with networked sensors • long-term data collection at scales • localized measurements • detailed information • integration of on-board processing, local storage, networking • complex filtering and triggering functions • application- and sensor-specific data compression algorithms

5. Introduction (cont.) • complete integration • produces smaller, low-power devices • increased power efficiency  flexibility • low-power radios with well-designed protocol • A specific habitat monitoring application • collection of requirements, constraints and guidelines • basis for the resulting sensor network architecture in the real-world • hardware and sensor platforms • patch gateways, basestations and databases • design and implementation of the essential network services • power management, communications, retasking and node management

6. Application Requirements • Field Stations and Research Overviews • Great Duck Island (GDI) • 44.09N, 68.15W, 237 acre, State of Maine • focus on basic ecology, large breeding colonies of Leech’s Strom Petrels and other seabirds • basic environmental parameters • light, temperature, humidity, pressure • entrance/exit events • the James San Jacinoto Mountains Reserve (JMR) • 33.48N, 116.46W, 29 acre, California • NSF Center : sensing infrastructures, multimedia sensors • monitoring ecosystems • response of vegetation to climate changes • acoustical sensing of birds for identification, estimation populations

7. Application Requirements (cont.) • General application requirements • Internet access • Hierarchical network • Field stations need host Internet connectivity and database systems • Habitats are located up to several kilometers • multiple patches of sensor networks • 3 to 4 patches of 100 static (not mobile) nodes • Sensor network longevity • run for 9 months from non-rechargeable power sources • multiple field seasons

8. Application Requirements (cont.) • Operating off-the-grid • operate with bounded energy supplies • renewable energy • Management at-a-distance • to monitor and manage sensor networks over the Internet • except for installation and removal of nodes • Inconspicuous operation • should not disrupt the natural processes or behaviors • System behavior • SNs exhibit stable, predictable, and repeatable behavior

9. Application Requirements (cont.) • In-situ interactions • Local interactions • initial deployment, maintenance tasks • PDA • query a sensor, adjust operational parameters, or simply assist in location devices • Sensors and sampling • light, temperature, infrared, relative humidity, barometric pressure • acceleration/vibration, weight, chemical vapors, gas concentrations, pH, noise levels

10. Application Requirements (cont.) • Data models • Archiving sensor readings for offline data mining and analysis • logs to databases in the wired, powered infrastructure • nodal data summaries, periodic health-and-status monitoring

11. System Architecture • lowest lever of the sensing application • autonomous sensor nodes • general purpose computational module • programmable unit • computation, storage, bidirectional communication • with analog and digital sensors • 2 advantages from traditional data logging systems • can be retasked, can easily communicate • application-specific sensing module • smaller and cheaper individual sensors • higher robustness • cooperation • multihop network, forwarding each other’s messages • in-network aggregation

12. System Architecture (cont.) • Sensor Gateway • each sensor patch • communicate with the sensor network and provides commercial WLAN • AP is co-located with the base station • additional computation and storage • enough energy from a car battery • Base Station • power, housing • communicates with the sensor patch via WLAN • WAN, persistent data storage • “custody transfer” model : SMTP messages, bundles

13. System Architecture (cont.) • User interaction • access the replica of the base station database • easy integration with data analysis and mining tools • remote control of the network • PDA-sized device, gizmo

14. System Architecture (cont.)

15. Patch Network Sensor Node Sensor Patch Gateway Transit Network Internet Client Data Browsing and Processing Basestation Base-Remote Link Data Service System Architecture (cont.)

16. Design and Implementation Strategies • Sensor Network Node • UC Berkely motes, MICA • single channel, 916MHz radio, 40kbps • Atmel Atmega 103 microcontroller running at 4MHz • 512KB nonvolatile storage • 2 AA batteries, DC boost converter

17. Design and Implementation Strategies (cont.) • Sensor Board • environmental monitoring sensor board • Mica Weather Board • barometric pressure module • 0.1 mbar from 300 to 1100mbar • humidity sensor • 1 picofarad (±3% relative humidity) • thermopile, passive infrared sensor • photoresistor, temperature • unique combination of sensors • variety of aggregate operations

18. Design and Implementation Strategies (cont.) • I2C analog to digital converter • 8 by 8 power switch • interoperability • 51 pin expansion connector

19. Design and Implementation Strategies (cont.) • Energy budget • run for 9 months, 2 AA batteries • 2200mAh at volts, 8,148 mAh per day • sleep state • turning off sensors, radio, putting processor into sleep mode • modify Mica motes with a Schottky diode

20. Design and Implementation Strategies (cont.) • Electro-mechanical Packaging • to protect the device, weather-proofing • Patch Gateways • CerfCube, StrongArm-based embedded system • CompactFlash-based 802.11b • Linux, IBM MicroDrive up to 1GB • Solar panel • Base-station installation • JMR : T1 line, GDI : two-way satellite connetion • turnkey system

21. Design and Implementation Strategies (cont.) • Database Management System • Postgres SQL database • time-stamped reading from sensors • health status of individual sensors • network • metadata • User Interfaces • GIS systems, statistics and data analysis packages • powerful interfaces to relational databases • web based interface, gizmo

22. Satellite router WWW power strip 4-port VPN router and 16-port Ethernet switch IBM laptop #1 DB Northern WAP Wireless bridge Power over LAN midspan IBM laptop #2 Burrow Camera Configuration Sensor Patch 12VDC, 0.9A Southern WAP 12V PoL Active Splitter network Axis 2401 Video Server Mica2-EPRB#2 916 MHz Axis 2130 PTZ South Web power strip IR Burrow Camera #1 IR Burrow Camera #5 DB IR Burrow Camera #6 IR Burrow Camera #2 IR Burrow Camera #7 IR Burrow Camera #3 ) Power over LAN Midspan Ethernet switch IR Burrow Camera #8 IR Burrow Camera #4 Wireless bridge 110VAC service Mica2-EPRB#2 Design and Implementation Strategies (cont.)

23. Sensor Network Services • Data sampling and collection • cost of data processing and compression against cost of data transmission • each packet 25bytes

24. Sensor Network Services (cont.) • Communications • hardware and a set of routing and media access algorithms • GAF (Geographic Adaptive Fidelity), SPAN

25. Sensor Network Services (cont.) • proposed approaches for scheduled communication • initial routing tree  set each mote’s lever form gateway  schedule nodes  sleep state  following level is awaken and packets are relayed  until completed  entire network return to sleep mode • path or subtree • low power MAC protocol • S-MAC, Aloha • turning off radio during idle periods

26. Sensor Network Services (cont.) • Network Retasking • to adjust the functionality of individual nodes • duty cycle, sampling rates … • tiny virtual machine, Maté • Health and Status Monitoring • monitoring the mote’s health and the health of neighboring motes • Health and monitoring messages sent to the gateway • not reliable transport, low latency, infrequently

27. Current Progress • deployed • two small scale sensor networks in JMR and GDI • all core architecture components • plan to add an intermediate tier of WLAN • need calibration or auto-calibration procedure • current focus • energy efficient strategies for multihop routing • will evaluate • intention • to develop and package a habitat monitoring kit • will be completed in 6 months • goal is to tackle the technical problems and to meet the application requirements set

28. Additional Materials • Node architecture advances • Problems observed in previous deployment • Size – motes were too large to fit in many burrows • Packaging – did not provide adequate protection for electronics or proper conditions for sensors • Reliability – last retreat talk; high rate of node loss, lack of scientifically meaningful environmental data • Power consumption – boost converter a minimal return at a high price • New generation of motes to address most of these concerns • Platform based on mica2dot • Primarily calibrated, digital sensors • Multiple application-specific packaging, power, and sensing options

29. Additional Materials (cont)

30. Additional Materials (cont)

31. Additional Materials (cont) • Miniature weather station • Sensor suite • Sensirion humidity + temperature sensor • Intersema pressure + temperature sensor • TAOS total solar radiation sensor • Hamamatsu PAR sensor • Radiation sensors measure both direct and diffuse radiation • Power supply • SAFT LiS02 battery, ~1 Ah @ 2.8V • Packaging • HDPE tube with coated sensor boards on both ends of the tube • Additional PVC skirt to provide extra shade and protection against the rain

32. Additional Materials (cont) • Burrow occupancy detector • Sensor suite • Sensirion humidity + temperature sensor • Melexis passive IR sensor + conditioning circuitry • Power supply • GreatBatch lithium thionyl chloride 1 Ah battery • Maxim 5V boost converter for Melexis circuitry • Packaging • Sealed HDPE tube, emphasis on small size

33. Additional Materials (cont) • Software architecture advances • Bi-directional communication with low-power listenting • 0.1% duty cycle • Parameter adjustment and query • Sample rate changes, sensor status queries • Improved power management scheme • Fine granularity through StdControl interface • 20 uA sleep mode • Multihop deployment planned for July • What it isn’t: GSK • Emphasis on simplicity and reliability, rather than generality • Compatible with most GSK server-side interfaces

34. Additional Materials (cont) • Application status • Sensor network • 26 burrow motes deployed • 12 weather station motes deployed (+2 for monitoring the insides of the base station case) • Another 14 are awaiting deployment within days • Redundant database setup online • 2 base stations logging packets to 2 database servers • Replication to Berkeley • Verification infrastructure • Overview cameras in place • Burrow cameras temporarily offline, wireless bridge problem • Video logging still needs to be synchronized with the mote data service

35. Additional Materials (cont) • Packaging evaluation • We observed what happens to motes when packaging fails • Battery venting, H2SO3 corroding the entire mote • Need to assemble the package correctly – we failed to create proper indication os a good seal • Majority of packages survived severe weather! • Still awaiting evaluation whether the package creates an environment suitable for sensing • Convective heating, etc.

36. Additional Materials (cont)

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42. Additional Materials (cont) • http://www.jamesreserve.edu/

43. Additional Materials (cont) • http://www.greatduckisland.net/

44. Conclusion • Habitat and environmental monitoring • important class of sensor network applications • collaborating with • College of the Atlantic and the James Reserve • low-level energy constraints of the sensor nodes • data delivery requirements • energy budget • Tight energy bounds and the need for predictable operation guide the development of application architecture and services.

45. Reference • http://www.jamesreserve.edu/ • http://www.greatduckisland.net/ • Robert Szewczyk, Joe Polastre, Alan Mainwaring, “Fresh from the boat: Great Duck Island habitat monitoring”, June 18, 2003 • Alan Mainwaring, Joseph Polastre, Robert Szewczyk, David Culler, John Anderson, “Wireless Sensor Networks for Habitat Monitoring”, ACM WSNA’02, September 28, 2002, Atlanta, Georgia, USA. • Joseph Robert Polastre, “Design and Implementation ofWireless Sensor Networks for Habitat Monitoring” • Kemal Akkaya, Mohamed Younis, “A Survey on Routing Protocols for Wireless Sensor Networks” • Wei Hong, “Overview of the Generic Sensor Kit (GSK)” • Robert Szewczyk, “Application-driven research on TinyOS platform”

46. Thank you!