I know the data from different sensors gets collected by the Border Router, and is displayed on the PC monitor using the ADWSN-UI tool. I want to know how the raw data can be interpreted?
The sensor data collected on the Border Router is represented by the ADWSN-UI tool in 3 forms.
These 3 tabs under the Monitor And Control label are
[Start] [Network Overview]…[Sensor Data].
[Start]: This contains the raw data packets in byte stream form, where the UDP packets containing sensor data from different wireless sensor motes are displayed. User need to have prior knowledge on which sensors are enabled on which motes, to interpret the received data. As this is in hexadecimal format, interpreting the results from this tab is not a straight task to anyone, unless prior information on sensors/motes is known.
The sensor data is followed by statistics information. The data highlighted in different colors above is for the following sensors (that is how this particular sensor mote is configured for in this example).
ADT75 - Temperature from ADT75
ADXL362 - Accelerometer (X, Y and Z axis)
SHT21 - Temperature and Humidity)
Ambient Light Sensor
The ADT75 data in the above is 0000CF41, and it is very difficult for anyone to understand what this value is in real life (decimal/floating point format).
IEEE-754 Floating-Point Conversion calculator (like the one attached in here) helps you in quickly interpreting the above data. http://babbage.cs.qc.edu/courses/cs341/IEEE-754hex32.html
For example, the ADT75 data in HEX format above is “00 00 CF 41”. If you read bytes in reverse order and enter in to the calculator as “41cf 00 00”, you see the result of 25.875 => This is the temperature value in centigrade degrees (in floating point form).
[Network Overview]: The network overview tab displays the payload received from the different sensor nodes under the Current Data column in floating point format as shown in the figure below. User need to know the sensors enabled on the nodes prior to identifying each sensor data. The figure displays all the four sensor data which are mounted on to the WSN Bunch boards.
[Sensor Data]: The sensor data tab displays the sensor data in form of graphs as shown in the below figure. The X-axis displays the time in the form of HH:MM:SS format and the Y-axis displays the magnitude (actual sensor data at particular time) and units for the sensor data. The figure displays all the four sensor data which are mounted on to the Bunch boards.