17-05-2012, 11:49 AM
Water Quality Monitoring System Using Zigbee Based Wireless Sensor Network
[attachment=22222]
INTRODUCTION
This work started after considering the critical
situation of the polluted natural water resources in
Malaysia. Keeping our water resources so that it is
always within a standard determined for domestic usage
is a crucial task. As the country is making its progress
through industrialization, our water resources are prone to
a threat of pollution especially from the industrial
activities. It is a challenge in the enforcement aspect as it
is impossible for the authorities to continuously monitor
the location of water resources due to limitation
especially in man power, facilities and cost of equipment.
This often lead to a too late to be handled situation.
For that, it is important to have such a monitoring
system with characteristics of autonomous, lower cost,
reliable and flexible. The use of automation in monitoring
task will reduce the reliance on man power at the
monitoring site thus reducing the cost.
RELATED WORKS
There are many works on the application of WSN for
monitoring system such as in [2], where Zigbee is used to
monitor the condition of long span bridge after
considering disadvantages of the currently used wire and
cable for data communications such as high installation
cost of communication and power supply for the sensors,
difficulty in the installation of steel pipeline for
protecting the cables, sensor data distortions due to
temperature changes on cables, noise affecting cables and
sensors etc. The Zigbee is used for the short distance
communication while CDMA (Code Division Multiple
Access) infrastructure was used for long distance
communication between sensors and the server system.
Another application of Zigbee in monitoring system is
found in [3] for parking management system.
HARDWARE DESIGN
A. Sensor Unit
A sensor unit is basically consists of several sensors
used to detect the predetermined parameters that indicate
the quality of water. In this work, three types of sensor;
pH sensor that senses the acidity of basicity of the water,
temperature sensor and turbidity sensor based on
phototransistor are used. All the sensors use battery for
its operation. The information being sensed by the
sensors are then converted into electrical signal and go
through the signal conditioning circuit that functions to
make sure the voltage or current produced by the sensors
is proportional to the actual values of parameters being
sensed. Then it is passed to a microcontroller or
microprocessor that processes it to the value
understandable by human.
SOFTWARE DESIGN
The GUI platform was successfully developed using
Borland C++ Builder programming that able to interact
with the hardware (coordinator) at the base station.
As shown in Fig. 5, three end devices are set for
connection to the coordinator with one of them linked
through the router to further extend the monitoring
distance. Firstly, the user has to create a connection from
the coordinator to the display unit, discover the
surrounding nodes and setting the data polling rate using
the buttons provided on the left side of the screen. The
links coloured in red means that the connection is not yet
established. When connections are establish the links
change its colour to green as in the following Fig. 6. This
is made so that it is easy for the user to identify the
connection status of sensor nodes in the network based on
the links status.
[attachment=22222]
INTRODUCTION
This work started after considering the critical
situation of the polluted natural water resources in
Malaysia. Keeping our water resources so that it is
always within a standard determined for domestic usage
is a crucial task. As the country is making its progress
through industrialization, our water resources are prone to
a threat of pollution especially from the industrial
activities. It is a challenge in the enforcement aspect as it
is impossible for the authorities to continuously monitor
the location of water resources due to limitation
especially in man power, facilities and cost of equipment.
This often lead to a too late to be handled situation.
For that, it is important to have such a monitoring
system with characteristics of autonomous, lower cost,
reliable and flexible. The use of automation in monitoring
task will reduce the reliance on man power at the
monitoring site thus reducing the cost.
RELATED WORKS
There are many works on the application of WSN for
monitoring system such as in [2], where Zigbee is used to
monitor the condition of long span bridge after
considering disadvantages of the currently used wire and
cable for data communications such as high installation
cost of communication and power supply for the sensors,
difficulty in the installation of steel pipeline for
protecting the cables, sensor data distortions due to
temperature changes on cables, noise affecting cables and
sensors etc. The Zigbee is used for the short distance
communication while CDMA (Code Division Multiple
Access) infrastructure was used for long distance
communication between sensors and the server system.
Another application of Zigbee in monitoring system is
found in [3] for parking management system.
HARDWARE DESIGN
A. Sensor Unit
A sensor unit is basically consists of several sensors
used to detect the predetermined parameters that indicate
the quality of water. In this work, three types of sensor;
pH sensor that senses the acidity of basicity of the water,
temperature sensor and turbidity sensor based on
phototransistor are used. All the sensors use battery for
its operation. The information being sensed by the
sensors are then converted into electrical signal and go
through the signal conditioning circuit that functions to
make sure the voltage or current produced by the sensors
is proportional to the actual values of parameters being
sensed. Then it is passed to a microcontroller or
microprocessor that processes it to the value
understandable by human.
SOFTWARE DESIGN
The GUI platform was successfully developed using
Borland C++ Builder programming that able to interact
with the hardware (coordinator) at the base station.
As shown in Fig. 5, three end devices are set for
connection to the coordinator with one of them linked
through the router to further extend the monitoring
distance. Firstly, the user has to create a connection from
the coordinator to the display unit, discover the
surrounding nodes and setting the data polling rate using
the buttons provided on the left side of the screen. The
links coloured in red means that the connection is not yet
established. When connections are establish the links
change its colour to green as in the following Fig. 6. This
is made so that it is easy for the user to identify the
connection status of sensor nodes in the network based on
the links status.