This week we focused again in understanding how to handshake between the two Arduinos, effectively giving us the signal strength between the transmitter and receiver. In a last act of desperation, we called Digi directly to troubleshoot issues we were having range testing with the XCTU software. We realized from talking with him that we had to connect the digital in to digital out on one of the XBees (we’ll call it XBee A) which completed the loop. Using the other XBee (B), a packet is sent from XCTU to XBee A. XBee A then directly relays that packet from the digital input to the digital output and sends it back to XBee B.
The XCTU software has a built in range testing function. Contained in this signal is the RSSI value, which is a dBm unit that ranges between -40 (strongest) and -100 (weakest) that is measured with this function. This data is not logged to a file, but rather is refreshed on the screen approximately every second as a number and colored graphical bar. We are also told how many packets have failed and been successful, as well as the percentage.
Using this data we were able to begin to create a map of the floor. Broadcasting from one static location, we moved around the floor with the other transceiver and recorded data from specific points around the floor. After this first test, which was broadcasted from the center of the floor, we then repeated the test by changing the broadcast location to the lobby. This test was taken at midnight after everyone had left the floor.
Our next steps would be to find a better way to log these data values. We would also like to explore more about how the orientation of the XBees has an affect on the symbol. We also should do the same test during the day while there are lots of people on the floor.