Download The Application of Wireless Sensor Network on Regional Environmental Protection

The Application of Wireless Sensor Network on Regional
Environmental Protection
WANG Weihong, LIN Yubing
College of Software, Zhejiang University of Technology, Hangzhou, P.R.China, 310032
[email protected]
Abstract Regional Environmental Protection is a hot issue. This paper firstly introduces the Wireless
Sensor Network, and briefly analyzes the problem in Regional Environmental. Then it proposed the
practicality and effectiveness by using the technology of WSN on Regional Environmental protection.
According to identical theory and example, it introduces the use of WSN on Information Collection,
Environment Monitoring and Safety warning of regional environment. Finally, this paper designed a
scheme of WSN on Regional Agriculture Environment Protection and concluded that Wireless Sensor
Networks is an important and effective mean for regional environmental protection.
Keywords Wireless Sensor Network, Regional Environmental Protection Information Collection;
Environment Monitoring; Safety warning;
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1 Introduction
With the development of wireless communications, electronic and microcomputer systems
technology, the wireless sensor nodes have been widely used in the worldwide. Wireless sensor nodes
are micro-system-on-chips with sensing, computing and communication capabilities. Wireless sensor
network is build automatically by a large number of wireless sensor nodes. WSN was highly concerned
by the industrial sector and the academic community of scholars, because of its low-cost, low power
consumption and multi-functional characteristics. And it was widely used in military, environment,
health, natural resources information collection, and so on. WSN was listed as one of the top 10
innovative technologies [1]. U.S. business magazine predict that wireless sensor networks will be one
of the next four major high-tech industries in future.
Regional Environment refers to a particular geographical space of the natural environment or social
environment. Different region faces different environmental problems. Wireless sensor networks are
widely used in the regional environmental protection. U.S. DARPA (Defense Advanced Research
Projects Agency) starts the SensIT (Sensor Information Technology) plan very early. By dropping a
large number of sensor nodes in a target area through aircraft, the nodes will monitor the changes in the
surrounding environment, and send data sent back to base. In this way, we can easily monitor the
environment changes. WSN in the regional environmental protection have very good prospects.
2 Wireless Sensor Network
Wireless sensor networks are composed by a large number of wireless sensor nodes. Wireless
sensor nodes scattered in various parts of the network for data collection and transfer data to clustering
node. Information collection node communicates with information processing centre through the wide
area network. Nodes communicate with each other in the own way, each node act as a router.
Wireless sensor network has features of low-cost, low power consumption and easy installation. In
addition, it still has the following characteristics: (1) self-organization: a wireless sensor network has the
general characteristics of Ad hoc. Nodes have the self-organization function. Nodes complete
communication through mutual coordination. (2). Dynamic network topology: sensor nodes structure
may change, because of energy depletion and other factors. At this time, the sensor network topology
will change dynamically. (3). Good Environment Adaption: As the sensor network nodes are smaller,
nodes do collection of information through self-organized without human intervention. So it can be
applied to the harsh environment that human hard to attach. (4). Network coverage is large in scale: the
nodes number of sensor in network usually attach to hundreds, thousands or even thousands, it can cover
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a large scale of area. (5). Resources are limited: because of price and conditions of the hardware, node’s
handling and computing capacity is relatively weak.
The features of Wireless sensor networks is comfortable to the region that human unable to reach.
It can set up in large-scale for certain regions. The emergence of wireless sensor networks makes it
convenient for the randomness data collection, and also avoids invasive destruction brought by the
traditional methods of data collection. Wireless sensor networks have very broad prospects, and they are
often used in military, environmental monitoring, medical, industrial smart furniture production,
building condition monitoring, complex machinery monitoring, urban transport, space exploration,
large-scale workshop and warehouse management, as well as airports, large-scale Industrial parks and so
on[2].
3 The Application of WSN on Regional Environmental Protection
Regional environment can be divided into natural regional areas, social regional areas, agriculture
regional environment, and tourism regional environment by function. They all have unique structure and
characteristics. Division of regional environment is designed to contrast with each other, and study and
solve environmental problems by its self characteristics.
With the rapid development of economic, environmental problems have become increasingly
prominent. As the development of region's industrial production and some other factors, the regional
environmental water pollution, atmospheric pollution, land pollution, and so on increasingly serious. As
an example to the Yangtze River Delta, with the high speed economic growth in Yangtze River Delta,
there is an undeniable fact that the region’s environmental conditions is deteriorating. The cross-border
water pollution, air pollution especially the SO2 pollution in the Yangtze River Delta region has been
very serious. "The Yangtze River Delta" has become China's new fragile ecological environment area [3].
Wireless sensor networks in designed of the needs of a particular application, is an
application-based network. Its features are particularly applicable to the regional environmental
protection. The application of Sensor networks for environmental monitoring change the model of single
fixed-point sensors in fixed-time and fixed-area in the past time. It can attaches the targets of
multi-angle observations (more types of sensors), synchronization, and continuous measurement. So the
data are more comprehensive, more representative. It more comfortable to described time and space
changes and found its internal relations of observation targets. According to the needs of regional
environment, we can design application-specific wireless sensor networks. The main application of
WSN on regional Environmental Protection can be divided into information collection, environmental
monitoring, security warning and so on.
3.1 Information Collection
Sensors can collect light, temperature, sound, humidity and other environmental data. In a regional
environment, on the basis of these data, we can make some decisions. In the agricultural regional
environment, the most common application of WSN is farmland information collection. The growth of
crops is impact by natural conditions, such as light, temperature and humidity. Especially, the
information of crop water demand is the basis for the adequate irrigation. We also can use sensor nodes
to tracking crop growth conditions; research the impact of environment change on crops, to provide
real-time decision-making. The volume of data on farmland is very large, using the network can be a lot
more convenient to achieve the long-distance data transmission, but if laying cable networks in the
farmland, on the one hand is not easy for farming, on the other hand costs higher [4]. So WSN is a good
option.
3.2 Environment Monitoring
The pollution areas that we need to monitor are always places that human as well as big device
hard to arrive. But wireless sensor networks can be quickly deployed, self-organization, high reliability
and is applicable such an environment. To monitor the atmosphere as an example, the traditional manual
sampling it can only be monitored the average concentration of gas at the scene within a certain period
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of time, can not provide real-time values, and the results of monitoring is great impact by the man-made.
The use of large-scale automation equipment is expensive. The device is too complex and difficult to
maintain. It is very hard to use in the country scale. The atmospheric monitor system based on wireless
sensor networks can effectively meet the needs of real-time monitoring [5]. The atmospheric monitor
system based on wireless sensor networks has the features of low-costing, easy implementation and high
reliability. Similarly, this similar application still can be used in the area of water pollution, soil pollution
and so on.
3.3 Security Warning
There are many potential safety problems hidden in Regional natural environment and industrial
production. These problems are always hidden, unexpected and unpredictable; it often leads to some
unpredictable consequences, resulting in huge losses. Wireless sensor network is an important means of
early warning. WSN is widely use in industrial production, construction, transport, medical and other
fields of security warning. To forest fires as an example, forest fire is one of the most serious disasters
that make destruction of forest resources, threats to human live environment. Prevention and monitoring
of forest fires has become a major research focus to the forest fire departments around the world. We can
build and import the wireless sensor networks to the monitoring of forest fires. The system is capable of
real-time monitoring of the measured parameters (such as temperature, relative humidity, etc.) and send
it to the monitoring center computer, the computer of monitoring centre analyzing the data, compare it
with forest resource base Data, then determine whether there is a potential forest fire in the field. This
will be an effective basis of the departments to make decision [6]. In the security protection of coal mine,
we also can use this type system.
4 A Scheme of WSN on Regional Agriculture Environment Protection
4.1 Main parameters of Regional Agriculture Environment
The typical application for Agriculture regional environment is collecting information of farmland
in a large area as a basis for decision making. Growth of crops is influence by various factors, mainly
the water content in soil, soil temperature, air temperature, air humidity and light intensity and other
factors. Regional Agriculture Environment has the following characteristics: (1) the coverage of
farmland in the region can be significant and broad. (2) The farmland environment are often not
available for laying the cable network, we can’t communicate through the cable network. (3) The
farmland is accessible, not very dangerous environment. However, the equipment needs to work in the
open environment, so it require for high equipment reliability. The characteristics of the agricultural
environment ask for a certain request for the sensor network node. The node work in these areas needs
to be small in size, environmental adaptability, low power consumption, pollution-free, and so on.
4.2 A scheme of WSN on Regional Agriculture Environmental Protection
According to the requirements above, we design a WSN scheme based on Regional Agriculture
Environmental. The purpose is to collect information of the farmland as an basis for decision making.
4.2.1 Network Structure
Sensor network is mainly composed by the communications nodes, sink nodes and application
server. Wireless sensor network nodes complete the data collection, preparation and communication
work. Cluster is formed by adjacent network nodes, each node send the data to the head node of the
cluster. The head node compressed the data and sends it to the Sink node. In fact, sink node is the
gateway nodes, is responsible for the network initiation, maintenance, data collection and send data to
the control center. The monitor center is responsible to data processing and network management. There
is some specific software on the control center that does the job of data processing and makes decision.
As farmland is a place that human can easy to reach, so we can artificial divide farmland into
multiple regions, each region as a cluster, form a cluster of network topology. And inside each cluster
assign a head node that responsible for the communication with gateway. And since the agricultural
environment may not have off-the-shelf cable network, so we can consider two communications
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structure. (1). the gateway communicates with the Server control center through the cable network. (2)
In the mobile networks such as GSM or CDMA coverage area. We can use the mobile base stations as a
transmission medium. The sink node send the data to base stations, and base station data then
transmitted it to the monitoring centre. The structure of this network can be show as follows:
Figure 1
Network structure
4.2.2 Node hardware design
Communications node is composed by the sensing element, the central processing unit, wireless
transceiver and power components. Based on agricultural environmental monitoring, we need to use
light, temperature and humidity sensors. The node structure is as follows:
Figure 2
Node hardware structure
In order to comprehensive monitoring light, air temperature, air humidity, soil temperature, soil
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moisture, the sensing modules need to use the optical sensors, temperature sensors and humidity sensors
to achieve the perception of different data collection. Microprocessor module is the main control unit.
It’s responsible for the collection of sensor data and does pretreatment of quantifying and coding. The
microprocessor also control communications units send data at appropriate time. We can use ATMEL
Company’s Atmega16 microprocessor. This MCU has faster, stronger anti-interference, the C-language
programming available advantages. Wireless communications module use Ember's 2402 EM radio chip.
The chip used IEE802.15.4 specifications and work in the band of 2400-2483SMHZ which is the
national free band.
The available power modules are Zn/MnO2 alkaline batteries, nickel-metal hydride batteries,
lithium ion batteries and so on. Each battery has its own characteristics. By contrast, lithium-ion
batteries have advantages of light weight, large capacity and energy density. Lithium-ion batteries can
meet the requirements from the volume, environmental adaptation, discharge stability, cost and so on. In
American ‘Great Duck Island’ experiment, the WEC sensor node is used the CR2450 lithium battery. In
this system, the use of lithium-ion battery is a relatively good option.
4.2.3 Software Design
Software systems can be divided into nodes software modules and control Center software modules.
Nodes software needs serial communication module, data conversion and amendment module. Serial
communication module responsible for communicate with gateway nodes, extracting sensors collecting
information and communication nodes address information from relevant data frame. Serial data
conversion module is responsible for collecting information from the sensors into digital information.
Monitoring Center software is information processing center. The software must receive and store the
data from network. To provide a friendly user interface. The software still needs to show the data in a
variety of ways and make relevant decisions.
This is a typical scheme of WSN on regional agriculture environment. Different Application has
different characteristics and parameters. It needs to use different network topology and different
hardware. We can design different scheme for specific application through the same line of thought. For
example, we can design Regional Atmospheric monitor system, Regional coal mine Safety Monitoring
System, Regional Forest Fire detection system and so on.
5 Conclusion
This paper introduces the characteristics of wireless sensor networks and its application on the
regional environmental protection. According to different theories and examples, it introduces the
application of wireless sensor networks on the information collection, environmental monitoring and
early warning of regional environment. Finally, this paper designs a typical wireless sensor networks in
regional agricultural environment. Compared with traditional methods at the regional environmental
protection, wireless sensor networks is a more convenient, real-time, reliable and effective means. It’s a
good option for regional environment protection.
Acknowledgments
This research was supported by the National High Technology Research and Development
Program of China(863 Program, 2006AA10Z235) and National Natural Science Foundation of China
under grant no.60873033.
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