-
Notifications
You must be signed in to change notification settings - Fork 2
Wireless
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/KT-Telemetry-Xbee-2new.jpg
Adding wireless telemetry is not difficult and can extend the capabilities of your UAV immensely. We recommend the APM telemetry kit (shown above), which uses Xbee wireless modules that have a range of more than a mile.
Forward pointing pins:
If you're going to mount your Xbee module in the front of your plane, you'll probably want the connectors pointing forward. In that case, solder four breakaway header pins in the IMU shield's "!TelemPort" holes as shown below:
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/IMG_4847.JPG
Now pull the black plastic strip off the pins (it's a little tight, but wiggling with a pair of pliers will do it), and bend them over 90 degrees as shown below:
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/IMG_4848.JPG
Downward pointing pins:
If you're going to mount your Xbee behind the APM board, you'll probably want the connector pins pointing downwards, so they don't take as much room. In that case, solder them to the bottom of the board.
Here's an example in an !EasyStar:
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/IMG_4879.JPG
And here how it looks seated properly in the plane, with an Xbee wireless telemetry module:
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/IMG_4880.JPG
Connect the !XtremeBee adapter (with the Xbee plugged in) to the APM shield pins as shown below via four individual connector wires. Your adapter should be in "Master" mode. ("Master" and "Slave" just reverse the TX and RX pins).
We recommend the DIY Drones four-wire Xbee cable, which comes with the official Wireless Telemetry kit shown above. It is designed to connect the !XtreamBee adapter to APM, as it will provide the neatest and safest connection. You should connect it as shown here (pins shown pointing up for clarity):
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/IMG_5065-1.JPG
If, however, you are creating your own telemetry kit or don't have the custom cable, you can also use a female-to-female servo connector cable for three of the four pins, and a jumper wire for the forth. Or just use four jumper wires. Both ways are shown in the pictures below.
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/IMG_4884.JPG
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/IMG_4841.JPG
If you're using the USB adapter in the official DIY Drones kit, simply connect it via a USB cable as shown:
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/IMG_4887.JPG
If you're using an !XtreamBee adapter on the ground side, connect it to a FTDI cable as shown below and plug that into your USB port. The adapter should also be in Master mode.
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/XtreemBee.png
Now you're done! Remember to select the right Xbee port (you can see which one has been assigned to the Xbee in the Windows Control Panel device manager) and a baud rate of 57k in the Mission Planner or other GCS when you're connecting.
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/xbeebaud.png
You can make your own telemetry kit if you'd like. The first thing to keep in mind is that you should use Xbee modules in a different frequency range than your RC equipment.
In general, we recommend 900Mhz Xbee modules, but in some countries 900Mhz is not approved. In those cases you can use 2.4Ghz Xbee modules. In that configuration, we use these Xbee Pro wireless modules. Setup can be a little tricky, so please see the comments below in this manual to see how other people have done it. In particular, we do not recommend the DIY Drones !XtreamBee adapter for those modules. Instead, try the Adafruit or Sparkfun adapters. Please note that the DIY Drones team will only support the recommended 900Mhz Xbee modules, so if you use something else please turn the community for help, not the DIY Drones developers.
Here is more discussion on how to pick the best frequencies for your setup.
All Xbee modules need adapters to work with APM. You have two choices:
- A DIY Drones XtreamBee adapters on the aircraft side, and a Sparkfun USB adapter board on the ground/laptop side with a USB cable.
- If you already have an FTDI cable, get two DIY Drones XtreamBee adapters.
If you have the DIY Drones Telemetry Kit, your Xbee modules are already set up and ready to go. But if you're setting up your own, here are some instructions:
The Xbee modules ship with a default of 9600bps, which you must change to match the APM's serial speed of 57600 bps; set your Xbee modules to match this speed. (If you want to use a different speed, you can change that by entering the line {{{#define SERIAL3_BAUD baud rate you want}}} in the APM_Config.h file.)
Connect each one of the them to the Sparkfun USB adapter board, plug the USB cable into your PC, and use Digi's X-CTU utility to select the right serial port and communicate with them. Remember to initially set the utility to 9600bps to contact the new Xbee modules, and than after you've changed the speed, change the utility's serial speed accordingly. You should also give the modules unique Network IDs (VIDs) so they will be paired. Just use any 3-digit number, and just make sure you have set it the same on both modules. (Note: If you will be flying near other UAV planes make sure to verify the Network IDs are unique and not used by others in your vicinity.)
This is what the setting should look like when you click "Read" in Modem Configuration tab of X-CTU (we're using 999 as the VID here as an example, and I've highlighted the correct baud rate):
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/Xbeescreenshot.PNG
Note: If you bought your Xbee modules from Sparkfun, rather than the official DIY Drones kit, please note that they sometimes ship with the wrong firmware. X-CTU may try to download new code, which will probably fail (cancel it). If your Xbee module is reporting that it's an XBP09-DM (rather than the correct XBP09-DP), do the following:
- If you have the XBP09-DP modules, you must download XBP09-DP firmware. If you have downloaded XBP09-DM firmware, it will kind-of work, but will fail at the PID-config screen.
- X-CTU will report the module as XBP09-DM. Ignore that. Go to the Modem Configuration tab and do the following:
- Select Modem as XBP09-DP, Function Set XBEE-PRO 900, Version 1002. It is important that you select 1002. Version 1061 does not work at first.
- Click the Show Defaults button under the Parameter View.
- Click the Write button under "Modem Parameters and Firmware".
- Go back to PC Settings, change Baud to 9600. Click Query. It will show XBP09-DM. Ignore that.
- Go back to Modem Configuration. Click Read. It should show XBP09-DP as the modem. Version 1002.
- Now select Version 1061.
- Click "Show Defaults"
- Click on the DD parameter and set it to 0. This step is important, otherwise the 1161 firmware download will fail.
- Click "Write". Now your firmware is XBP09-DP Version 1161.
- Now change the baud rate and Modem VID, redownload and you should be good to go.
It will still show XBP09-DM in the PC Settings Query. Don't worry about that.
If you open up a terminal program on your laptop (you can use the Arduino IDE's serial monitor for this, too), select the correct serial port, and set the baud rate to whatever you set the Xbee modules to above (the default is 57600). Once you do this, you should see APM telemetry coming in. Anytime there is a "Serial3.println" in the code, that data will be sent through the Xbees to the ground. You can record any data you want, and even datalog from the ground! You can also open the Ground Station software, setting the right port and baud speed) and it should begin to show APM data.
Additionally, if you want to test the range of your Xbee link, connect the plane-side Xbee module's RX and TX pins together to create a loopback circuit and use the X-CTU utility's range test function. For the modules we are using you should get around a mile.
Note: If you've got an Xbee attached to your APM, the USB cable will probably not provide enough power by itself to drive them both. Please also have an ESC and !LiPo connected to the RC pins to provide additional power. (You can tell that you've got a low power ("brownout") condition if you just have the red C LED blinking dimly, or the APM board is otherwise intermittent.)
!ArduPilot Mega has four serial ports so all the usual Arduino serial commands now take a specifier to say which port you want to read from or write to. For example: Serial1.print(), Serial2.print(). The port connected to the USB/FDTI connector is Serial0. The port connected to the Telecom pins is Serial3.
Here's a quick demo that will print to all four ports so you can check to see that your Xbee connection is working. Here are the instructions on how to use it:
1) Plug your Xbee into one USB port and your APM into another. Use Arduino to load the demo code, and then in the Arduino IDE set the serial port to the one assigned to your APM board. Then open the serial monitor, setting the baud rate to 115200. You should see "Port 0" repeated as follows, showing the output from the APM's USB port:
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/xbeetest2.png
2) Now switch the serial port to the one your Xbee is assigned to and reopen the serial monitor, setting the baud rate to 57600 (which is the speed your Xbees should already be programmed for). You should now see "Port 3" repeated, showing the output from APM's Xbee port:
http://ardupilot-mega.googlecode.com/svn/ArduPilotMegaImages/xbeetest1.png
IMPORTANT NOTE: Sometimes Xbee modules get corrupted due to spurious signals. If you're finding that yours stops working (green LED on Adafruit adapter doesn't come on), instructions to reload the firmware follow:
Using the Sparkfun USB explorer board:
- Take the module out of the interface board.
- Connect the interface board to the computer.
- Open X-CTU make sure Baud Rate is set to 9600
- Go to "Modem Configuration"
- Put a check in the "Always update firmware" box
- Select proper modem from drop down menu (for the 900Mhz ones recommended above select "XBP09-DP"; for 2.4GHZ Xeebee Pro 2 select "XBP24-B")
- Click on the "Write" button. After a few seconds of trying to read the modem, you will get an Info box that says Action Needed. At this point, CAREFULLY insert the module into the interface board. After a few seconds, this should trigger a reloading of the firmware.
- You may get the info box again a short while after; if so just repeat the previous step a few times and it should work.
- This will put the module back to 9600 baud. Set your X-CTU PC settings to that and test it. It should report back that it's recognized.
- Once you've confirmed that it's working again, make you sure you reset its baud rate (typically 57k for APM) and VID number to match your other module.
(Thanks to Doug Barnett for these tips)