3D Robotics

Connecting to APM 2.5 via Bluetooth


If you'd like to connect to APM 2.5 wirelessly but don't need the long-distance reach of the 3DR radios, you can use the Bluetooth connection built in to your laptop, along with a Bluetooth module. 

Here's what you'll need to do this:

Once you get the Bluetooth module, you need to set it to the right baud rate. A guide to all the commands it can use is here, but here's the short form:

  1. If you have a USB Xbee adapter or an FTDI cable,  use that to connect the Bluetooth adapter directly to your PC. If you don't have those, you can also do with wirelessly over Bluetooth using the Serial-over-Bluetooth process described below, but I haven't tried that myself.
  2. With any terminal program (TeraTerm, HyperTerm, etc), select the COM port assigned to the cable/adapter the Bluetooth module is plugged into, and set the baud rate to 115k.
  3. Within 60 seconds of powering on the Bluetooth module, enter "$$$". This should produce a "CMD" command prompt.
  4. Type "SU,57"[Return]. This will set the baud rate to 57k. It will not take effect until you power cycle the module.
  5. Now you can unplug it from the USB Xbee adapter or FTDI cable. Plug it into the Xbee adapter board, and with the APM adapter cable, plug it into the APM telem port.
  6. Power APM with the Power Module. (Don't power it via USB, since you can't use wireless and USB at the same time)
  7. On your PC, go into the Windows Control Panel/Hardware and Sound/Devices and Printers. Select "Add a Bluetooth device". It should see the Bluetooth module, which will be called "FireFly". Connect to it. Say OK to any boxes that come up about pairing codes.
  8. Now if you look in your Control Panel/Device Manager/Ports (COM & LPT), you should see two new ports called "Standard Serial over Bluetooth link" with COM numbers after them. You'll be using the first (lower) of the two.
  9. Go into the APM Mission Planner and select that port, with the baud rate of 57k.
  10. You should now be able to connect to APM over MAVLink via Bluetooth!




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  • Hi there,

    Coming on board a bit late but I just got one of those JY-MCU (HC-06) BT module with default baud rate of 9600. Is there any way to change the baud rate without having FTDI or Xbee adapter?

    The above instruction says it can be done wirelessly but it doesn't clearly explain it. 

    If there is any change to change the baud rate from 9600 to 57600, would you please let me know? I do not have an FTDI cable and trying to avoid buying it because it will be used only once and never again and it is more than what I paid for the BT module.

  • There is another Android based GCS that natively communicates over Bluetooth and is designed for phone sized screens, and will run on android 3.2 and up:


    Its a continuation of Copter-GCS, and is fully featured including a full mission planner, follow-me, guided mode, pid editor, hud, among other features.
  • @Bill: Nice module. I want to be able to setup a UDP (OLSR) protocol routing using Wi-Fi. The main thing I want is this protocol to be used via Wi-Fi. Would this be supported as well, if so I would like to know how . As I understand, this module must fit into my arducopter right?

  • Developer
    @Chris: I'll try to post up instructions in the next couple of days. I'm using TCP infrastructure at the moment, but I have had UDP infrastructure working as well. Not been so successful with standalone AP, but then I haven't tried too hard on that yet, but probably just needs some focus. I'll see what I can do.
  • 3D Robotics

    Bill: I have that module but can't figure out how to set up a virtual serial port over it. Do you have a link to a tutorial? I can't even figure out how to set it up as an AP. 

  • Developer
    @shyan: you can use this https://www.sparkfun.com/products/10822 to connect via WiFi. MP supports TCP or UDP connections so it supports this. It's working great for me.
  • Hi Chris,

    This is a good feature. Going forward, Is there a module (from 3DR) to communicate via a Wi-Fi too and does Mission Planner already support this feature?


  • There already is:  Andropilot

  • are we going to see some apps on mobile phones soon ;)

  • I have thought about this alot and the Bluetooth 4.0 Low-Energy has lots of potential to be the 'wireless USB' cable and would remove the need to choose COM ports. It would also have an added advantage it would work on new iPhones and iPads. You could build a board that mated Bluetooth 4.0 LE with the Ground-based Xbee/3DR. Do you think people would find such a board useful? I am going to try and build one.
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