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Wireless Sensor Networks. Nuwan Gajaweera Research Engineer. Outline. Motes & Wireless Sensor Networks WSN Applications TinyOS WSN research at the Dialog Lab. Motes & Wireless Sensor Networks. Sensor. Radio Transceiver. Analog I/O Ports. Microcontroller. D/A. Sensor.
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Wireless Sensor Networks Nuwan Gajaweera Research Engineer
Outline • Motes & Wireless Sensor Networks • WSN Applications • TinyOS • WSN research at the Dialog Lab
Sensor Radio Transceiver Analog I/O Ports Microcontroller D/A Sensor External Memory A/D Digital I/O ports 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)
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
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,
“Cricket” Mote • 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
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
Mica2 • Extremely popular mote • 8-bit AVR Controller • FSK radio • Data-logger flash
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
Leaf Node Base Station Data Mule 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