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Wireless Sensor Networks
Nuwan GajaweeraResearch Engineer
Outline
• Motes & Wireless Sensor Networks
• WSN Applications
• TinyOS
• WSN research at the Dialog Lab
Motes & Wireless Sensor Networks
Mote
• A very low cost low power computer• Monitors one or more sensors• A Radio Link to the outside world• Are the building blocks of Wireless Sensor
Networks (WSN)
External Memory
Dig
ital I
/O p
ort
s
Radio Transceiver
An
alo
g I
/O P
ort
s
Microcontroller
A/D
D/A
Sensor
Sensor
Wireless Sensor Network
“A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices using
sensors to cooperatively monitor physical or environmental conditions, such as
temperature, sound, vibration, pressure, motion or pollutants, at different locations.”
- Wikipedia
Wireless Sensor Networks
• Formed by hundreds or thousands of motes that communicate with each other and pass data along from one to another
• Research done in this area focus mostly on energy aware computing and distributed computing
Super Node
Links to Other networks or Similar Super Nodes
Motes
WSN Applications
• Environmental/Habitat monitoring • Acoustic detection • Seismic Detection • Military surveillance • Inventory tracking • Medical monitoring • Smart spaces • Process Monitoring
Habitat Monitoring on Great Duck Island
• http://www.greatduckisland.net/
• Intel Research Laboratory at Berkeley initiated a collaboration with the College of the Atlantic in Bar Harbor and the University of California at Berkeley to deploy wireless sensor networks on Great Duck Island, Maine (in 2002)
• Monitor the microclimates in and around nesting burrows used by the Leach's Storm Petrel
• Goal : habitat monitoring kit for researchers worldwide
FireBug
• Wildfire Instrumentation System Using Networked Sensors• Allows predictive analysis of evolving fire behavior• Firebugs: GPS-enabled, wireless thermal sensor motes
based on TinyOS that self-organize into networks for collecting real time data in wild fire environments
• Software architecture: Several interacting layers (Sensors, Processing of sensor data, Command center)
• A project by University of California, Berkeley CA.
Preventive Maintenance on an Oil Tanker in the North Sea: The BP Experiment
• Collaboration of Intel & BP
• Use of sensor networks to support preventive maintenance on board an oil tanker in the North Sea.
• A sensor network deployment onboard the ship
• System gathered data reliably and recovered from errors when they occurred.
• The project was recognized by InfoWorld as one of the top 100 IT projects in 2004,
• Basically a location-aware mote. • Includes an Ultrasound transmitter and receiver.• Uses the combination of RF and Ultrasound technologies
to establish differential time of arrival and hence linear range estimates
• Based on Cricket Indoor Location System developed by a MIT researcher Nissanka Bodhi Priyantha
“Cricket” Mote
TinyOS
• What is TinyOS– open-source operating system– wireless embedded sensor networks– component-based architecture
• Developed at UCB in collaboration with Intel Research• Current Stable Version is 1.1.15• TinyOS 2.0 (T2) released on 6/11• Main Ideas –
– Low complexity– Conserve power – sleep as frequently as possible
• Written in nesC – next generation C compiler
Different Targets
mica mica2 mica2dot micaz
telos telosb rene2 pc
Mica2
• Extremely popular mote
• 8-bit AVR Controller
• FSK radio
• Data-logger flash
Our contributions to the WSN world
Mica2 Clone
Data Mule
• DataMule – a mobile entity present in the environment that will pick up data from the mote when in range, buffer it, and drop off the data at base station– ex: People, Vehicles, Livestock
Data Mule
Data Mule
Base Station
Leaf Node
Data Mule
Data Mule
Base Station
Data Mule - Applications
• Collecting a data in a sparse sensor network
• Tracking movement of mobile elements– Vehicles– Livestock– Wild Animals
Data Mule
Base Station
Data Mule - Research undertaken
• Development of a TDMA/CSMA hybrid MAC– TinyOS currently has a CSMA MAC– Hope to improve throughput by employing TDMA– Time is divided into transmission periods and contention periods– Nodes will contend with each other to join “the transmission
group” during the contention period.– Nodes in the transmission group will be allocated a time-slot in
the transmission period.
• Development of data storage engine optimized for fast retrieval
Thank you..