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ATZB-EVB-XXX-XXX User Manual
AVR-09-2011
The pattern of antenna is wide. The following facts should be considered. In far-field
zone, it is a horizontal plane normal to the dipoles where electromagnetic radiation
appears stronger. Contrarily, at distances of several centimeters the pattern is more
complex. Approximate field patterns are given in the ZigBit datasheet [1].
Handle the external antenna with care to avoid mechanical damage.
5 WSNDemo Application
5.1 Overview
The network performance of ZigBit platform is demonstrated with the WSNDemo
application which is based on the BitCloud software API. This application comprises
the embedded firmware, which supports functions for coordinator, router and end
device, and the GUI part – the WSN Monitor which is run on a PC.
Thanks to the WSNDemo application, the ATZB-EVB (MeshBean) boards are
organized into a set of nodes constituting a wireless network. The LEDs of a board
indicate the board current state and activities. End devices and routers read from the
onboard sensors and send the readings to coordinator in packets. End devices also
follow a duty cycle, waking up occasionally to transmit the sensor data. That data is
displayed on WSN Monitor panes as temperature, light and battery level
measurements.
End device is mostly sleeping, and it wakes up shortly each 10 seconds for activities.
During the sleep period, you can force end device to wake up by pressing the
SW1
button. Router sends data each 1 second. Using UART, the coordinator transmits the
received packets, along with its own sensor data, to the GUI application (WSN
Monitor).
The WSN Monitor visualizes the network topology in a form of tree. It also displays
the node parameters like node addresses, node sensor information and node link
quality data.
Measured in dBm, RSSI indicates link’s current condition. The RSSI resolution is 3
dBm. LQI is a certain numeric value defined within the 0…255 range to measure the
link quality. Larger values mean better link, while values close to zero indicate poor
connection.
In regard to the WSNDemo, Section 5.4 describes how to use the boards. GUI is
described in Section 5.6. Further instructions are given in Section 5.7.
The application is delivered with source code included (see 10.7). It is implemented
on top of the BitCloud API and it can be modified as described in Section 8.
With WSNDemo, the number of routers and/or end devices used is limited only by the
network parameters described in Section 8.4.
