Wireless%20Sensor%20Networks%20for%20Habitat%20Monitoring - PowerPoint PPT Presentation

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Wireless%20Sensor%20Networks%20for%20Habitat%20Monitoring

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Seabird colonies are very sensitive to disturbances. Team 8 Feng Kai and Michael Thomsen ... Storm Petrels and other seabirds. James San Jacinto Mountains Reserve ... – PowerPoint PPT presentation

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Title: Wireless%20Sensor%20Networks%20for%20Habitat%20Monitoring


1
Wireless Sensor Networks for Habitat Monitoring
  • Alan Mainwaring, Joseph Polastre, Robert
    Szewczyk, and David Culler, June 2002

Presented by Team 8 Feng Kai and Michael
Thomsen, September 2004
2
Outline
  • Habitat monitoring
  • Network Requirements
  • System Architecture
  • Hardware and Design
  • Results

3
Why?
  • Why are we interested in Habitat Monitoring?
  • Focus attention on a REAL network
  • Some problems have simple concrete solutions,
    while others remain open research areas
  • Application driven approach separates actual
    problems from potential ones, and relevant issues
    from irrelevant ones
  • Collaboration with scientists in other fields
    helps define broader application space as well as
    scientific requirements

4
Scientific Motivation
  • How much can they vary?
  • What are the occupancy patterns during
    incubation?
  • What environmental changes occurs inthe burrows
    and their vicinity duringthe breeding season?
  • Questions
  • What environmental factors make for a good nest?

5
Scientific Motivation
  • Collect detailed occupancy data from a number of
    occupied and empty nests
  • Validate a sample of sensor data with a different
    sensing modality
  • Augment the sensor data with deployment notes
    (e.g. burrow depth, soil consistency, vegetation
    data)
  • Try to answer the questions based on analysis of
    the entire data set
  • Methodology
  • Characterize the climate inside and outside the
    burrow

6
Scientific Motivation
  • Solution
  • Deployment of a sensor network
  • The impact of human presence can distort results
    by changing behavioral patterns and destroy
    sensitive populations
  • Repeated disturbance will lead to abandonment of
    the colony
  • Problems
  • Seabird colonies are very sensitive to
    disturbances

7
Field Stations
  • Great Duck Island
  • Almost 1 km2 (237 acre) remote island
  • Coast of Maine
  • Large Breeding colonies of Leechs Storm Petrels
    and other seabirds
  • James San Jacinto Mountains Reserve
  • Small 0,1 km2 (29 acre) ecological preserve
  • Near Idyllwild, California(about 100 km east of
    LA)
  • Studying nest boxes, and ecosystems over time

8
Application Requirements
  • Hierarchical network (local networks over longer
    distances)
  • Sensor network longevity (at least 9 months)
  • Operating off-the-grid (battery or solar cells)
  • Remote management (personnel just available 2-3
    months)
  • Inconspicuous operation (should not disrupt
    natural processes or behaviors under study)
  • System behavior (stable, predictable and
    repeatable behavior)
  • In-situ interactions (during deployment and
    maintenance)
  • Sensors and sampling (light, temperature, IR,
    humidity, pressure)
  • General Requirements
  • Internet access

9
System Architecture
10
Sensor Nodes
  • Sensor Nodes
  • Separated into two logical components
  • Computational module (MICA)
  • Sensing Module (Weather board)
  • Sensor nodes communicate andcoordinate with one
    another
  • Battery powered
  • Small (5 x 3.8 x 1.25 cm3)
  • Mechanically robust
  • Weather-proofed (but ventilatedto avoid data
    distortion)

11
Sensor Nodes
  • Computational Module
  • Mica Platform
  • Atmel Atmega 103 micro controller _at_ 4 MHz
  • 512 kb Flash memory
  • 916 MHz, 40 kbps radio
  • 2 AA batteries w/boost converter

12
Sensor Nodes
  • Sensor Module
  • Mica Weather Board
  • Temperature
  • Photoresistor
  • Barometric pressure
  • Humidity
  • Passive IR (Thermopile)
  • Designed to coexist with other sensor boards
  • Low variation when interchanged with other
    sensors of same model

13
Power Management
  • Sensor Node Power
  • Limited Resource (2 AA batteries)
  • Estimated supply of 2200 mAh at 3 volts
  • Each node has 8.128 mAh per day (9 months)
  • Sleep current 30 to 50 uA (results in 6.9 mAh/day
    for tasks)
  • Processor draws apx 5 mA gt can run at most 1.4
    hours/day
  • Nodes near the gateway will do more forwarding

75 minutes
14
Power Management
  • Compression
  • Does the compression require more power than
    transmission?
  • Even if it does it may be worthwhile to compress
    if data must pass through many nodes
  • 2 - 4 times reduction by combining
  • Delta compression and
  • Standard compression algorithm

15
Gateway
  • Function
  • Relay sensor patch network data to base station
  • Coordinate the activity within the sensor patch
  • Provides additional computation and storage
  • Gateway to base station distance apx 100 m
  • Hardware
  • Strong-Arm based embedded system (CerfCube)
  • Runs an embedded version of Linux
  • Compact Flash memory
  • 2.5 W supplied by solar cells and lead-acid
    battery

inches
16
Base Station
Base Station
17
The Gizmo
  • In situ Interaction (Planned)
  • PDA-sized device
  • Communicate directly with the sensor patch
  • Direct communication to the mote
  • Provides fresh readings
  • Interactively control the network (sampling
    rates, power management etc)
  • Useful during initial deployment andretasking of
    the network

18
Communication
  • Routing
  • Routing directly from node to gateway not
    possible
  • Approach proposed for scheduled communication
  • Determine routing tree
  • Each gate is assigned a level based on the tree
  • Each level transmits to the next and returns to
    sleep
  • Process continues until all level have completed
    transmission
  • The entire network returns to sleep mode
  • The process repeats itself at a specified point
    in the future

19
Network Retasking
  • Network Retasking
  • Initially collect absolute temperature readings
  • After initial interpretation, could be realized
    that information of interest is contained in
    significant temperature changes
  • Full reprogramming process is costly
  • Transmission of 10 kbit of data
  • Reprogramming application 2 minutes _at_ 10 mA
  • Equals one complete days energy
  • Virtual Machine based retasking
  • Only small parts of the code needs to be changed

20
Conclusion
  • Paper conclusion
  • Two small scale sensor networks deployed atGreat
    Duck Island and James Reserve (one patch each)
  • Results not evaluated
  • No calibration was done, development of
    auto-calibration procedure suggested
  • Future
  • Develop a habitat monitoring kit

21
Problems
  • 2002 Deployed Network
  • No new science about petrel breeding behavior,
    many insights into how to build sensors that
    would yeild that science
  • Base Station laptop must run unattended (problem
    with unscheduled system reboots (mostly fixed))
  • Temperature Sensors
  • Measured temperature inside the enclosure, rather
    than ambient temperature
  • Good correlation with Cost Guard measurements on
    cloudy days
  • Batteries
  • Only operational down to 2.5 V (expected down to
    1.6V)

22
Problems
  • 2002 Deployed Network
  • Rain affecting the humidity sensor and
    short-circuiting the battery

23
Additional References
  • R. Szewczyk, J. Polastre, A. Mainwaring, D.
    Culler Lessons from a Sensor Network
    Expedition, UC Berkerly, Jan 2004
  • J. Polastre Design and Implementation of
    Wireless Sensor Networks for Habitat Monitoring,
    Research Project, 2003
  • www.greatduckisland.net

24
2003 Network
  • New design
  • Lithium battery based
  • New enclosure
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