Technical Review
Jessica Curry-ECE 4007
L02/Milor
Heat Sensoring
Wireless Temperature Sensor Networks
Introduction
Wireless temperature sensor technology is being used to predict fires, notify
firefighters of fire locations, and warn residents of when to evacuate homes. This paper
focuses on the commercial applications of wireless temperature sensor networks, the
underlying technology for these devices, and how to implement the technology.
Commercial Applications
California wildfires have inspired new applications for wireless temperature
sensors. San Diego State University Scientists are creating a system called FireAlert
which has sensors able to detect a fire up to six miles away. FireAlert uses an early
warning detection system to help residents evacuate early and allow firefighters to know
where a fire is occurring. Thirteen sensors, at $12000 apiece, will be placed in the Santa
Margarita Ecological Reserve near San Diego [1]. UC Berkeley professors and students
are building the FireBug system to collect real time data in wildfire environments in order
to predict future fire behavior [2].
Underlying Technology
FireAlert is a battery-free system that uses energy management technology to
supply power to devices twenty four hours a day, seven days a week for over twenty
years. The embedded smart processing uses software algorithms to detect the signature
of a wildfire in less than four minutes and minimize false alarms [3].
A network of wireless sensors uses a control layer to process sensor data and a
central base station to communicate interactively with the sensor network. Each layer
communicates through interfaces. The controller, which is usually a personal computer,
will send commands to the base station, provide storage for mote data, and conduct data
processing [2]. The FireBug sensor network uses a base station node and several FireBug
Technical Review
Jessica Curry-ECE 4007
motes, which are each equipped with five sensors that include temperature and humidity,
barometric pressure, GPS, an accelerometer, and light intensity. The mote network is
operated by a command center passing commands through the base station. Each mote
sends the data from its sensors back to the base station which relays the data back to the
command center where data is then stored and processed [4].
Implementation
Firebug uses Surge software, a java program for displaying multihop routing
topology in sensor networks. Surge detects all motes in the wireless network, displays
the mote identification number, and presents the number of messages sent from each
mote [2]. The multihop software uses the shortest-path first algorithm with a single
destination node and active two-way link to find the router for receiving and transmitting
packages [5]. MH6 is the self-organizing network routing protocol. Each sensor uses a
Leadtek 9546 GPS receiver, which has an external antenna mounted to a sensor board.
The software for programming the motes uses low level TinyOS embedded operating
system to process the original message and route message [2].
Multiple levels allow for different applications to take place. Some components
will process sensor readings, filter and distill data streams for the application, acquire the
radio channel, and frame data streams into packets that receiving motes will recognize. A
typical top-level application will receive and process a stream of filtered sensor readings
and then deliver important messages to the network. The notification messages are
received and then transmitted to the other motes [6].
References
[1]
Ivanhoe Broadcast News, “Fire Sensors-Ecologists Deploy Wireless Sensors for
Early Detection of Wildfires,” [Online Document], 1 Sep. 2005, [cited 1 Sep.
2008], Available HTTP:
http://www.sciencedaily.com/videos/2005/0901-fire_sensors.htm
[2]
FireBug Wildland Fire Monitoring System, “Design and Construction of a
Wildfire Instrumentation System Using Networked Sensors,” [Organization
Website], [cited 1 Sep. 2008], Available HTTP:
http://firebug.sourceforget.net/
[3]
Ambient Control Systems, “Detection Products,” [Company Website], [cited
1 Sep. 2008], Available HTTP:
http://www.ambientalert.com/fa_systems/fa_detect.html
[4]
G. Martin, “An Evaluation of Ad-hoc Routing Protocols for Wireless Sensor
Networks,” B.S. dissertation, Dept. Software Eng., Newcastle Univ., Newcastle,
U.K., 2004.
[5]
C. Shuai, Z. Xianxin, C. Lingling, and L. Xiaowei, “Temperature measurement
through wireless sensor networks,” Proceedings of the SPIE, 2006, vol. 6280,
pp. 62801J.1-62801J.7.
[6]
D. Culler, D. Estrin, and M. Srivastava, “Overview of Sensor Networks,” IEEE
Comput. Special Issue in Sensor Networks, vol. 37, no. 8, pp. 41-49, Aug. 2004.