Although the Parallax GroundStation provides useful information about the ELEV-8 v3 when it is connected to your computer with a USB cable, it is even more useful when that connection is wireless - allowing you to see real-time telemetry data including data from each of the sensors on the ELEV-8 v3 while it is in flight using your computer. Whether you are a teacher, student, or hobbyist, a wireless telementry link will provide valuable information for learning and experimenting.
Creating this wireless connection will require several components and setup using Digi's XCTU configuration tool.
If you have not done so already:
If you have an ELEV-8 Quadcopter you must register it with the Federal Aviation Administration's UAS Registry [3] before flying outdoors.
The ELEV-8 v3's Flight Controller has a socket that is compatible with XBee modules from Digi. Because the radio link used by the transmitter and reciever for flying your ELEV-8 v3 operates in the 2.4 GHz band, it is important to use XBee radios that operate in a different freqency band. In the United States, the best band for this application is the 900 MHz band (868 MHz will be required instead in some countries). This frequency band allows both good range and data throughput.
WARNING: Do NOT attempt this with 2.4 GHz radio modules, as their signals may be detected by your quadcopter's receiver and cause unexpected or dangerous behavior!
For this activity you will need:
If you wish to source telemetry parts individually, you will need the following:
In order to get all of the data from the ELEV-8 v3 Flight Controller to the GroundStation software on your computer, the XBee modules have to be set at a high enough buad rate to support a large amount of data throughput. 57600 baud was chosen as a good comprimise between a solid signal and a fast enough transfer rate. By default, these XBee Modules are set to communicate at 9600 baud.
Do not power on an XBee Module with an antenna connector without an antenna attached. Powering up a radio module without an antenna attached can damage the module.
To change the baud rate for each module:
Once you have have configured both XBee modules, you are ready to install one of them on your ELEV-8 Flight Controller.
You have two options for attaching the antenna: 1) attaching the antenna directly to the XBee module (see warning below!) or 2) use an RPSMA extension cable between the XBee module an antenna for strain relief.
Caution - a crash (even a minor one) could damage or destroy the XBee if the antenna is installed directly onto the XBee module - follow Option 1 at your own risk
Note: If you have previously gone to the trouble of balancing your quadcopter's frame [14], you may want to re-balance it after these hardware additions have been made.
If you wish to make the receiving end of your telemetry link semi-permenant and provide it some protection, you can use a short piece of large diameter (1.25" or 1.5") clear heat-shrink tubing to enclose the XBee Module and USB Adapter Board. This is completely optional, but dials up the "cool factor."
Do not power on an XBee Module with an antenna connector without an antenna attached. Powering up a radio module without an antenna attached can damage the module.
WARNING! When using wireless telemetry during flight, bring a fellow operator to monitor your GroundStation software. IT IS DANGEROUS TO SPLIT YOUR ATTENTION BETWEEN YOUR QUADCOPTER IN FLIGHT AND THE GROUNDSTATION SOFTWARE!
To verify that you have successfully built the wireless telemetry link between your ELEV-8 v3 and the Parallax GroundStation software, do the following:
Do not power on an XBee Module with an antenna connector without an antenna attached. Powering up a radio module without an antenna attached can damage the module.
Links
[1] https://learn.parallax.com/node/1196
[2] https://learn.parallax.com/node/1186
[3] http://www.faa.gov/uas/registration/
[4] https://www.parallax.com/product/80300
[5] https://www.parallax.com/product/32480
[6] https://www.parallax.com/product/32411
[7] https://www.parallax.com/product/32410
[8] https://www.parallax.com/product/32400
[9] https://www.parallax.com/product/805-00006
[10] http://www.digi.com/products/xbee-rf-solutions/xctu-software/
[11] https://www.parallax.com/downloads/parallax-groundstation-software-windows
[12] https://www.parallax.com/downloads/elev-8-flight-controller-firmware
[13] http://www.ftdichip.com/Drivers/VCP.htm
[14] http://node/1221