Bluetooth Serial Communications with the APM

I've heard some people mention using bluetooth to communicate with microcontrollers as replacement for a serial or USB & FTDI. Recently some small bluetooth serial modules have become available from large electronics retailers and smaller ones that operate on large internet auction websites. They can be purchased now for just a few bucks. The module has all the bluetooth components integrated and takes 3 volt TTL level RS232 signals. It comes in a surface mountable pcb package, however breakout boards are available that have easily hand solderable headers, and a 3V regulator etc:


3689424898?profile=originalAlthough these modules are 3V, they will work with the 5V APM, so long as there is at least a 1K resistor on the RXD (which is what the 5V TX line on the APM will drive). The 3V signal from the module to the APM is OK as it is.


Starting communication is a matter of pairing with the device which comes up as 'linvor', then enter the default pin (0000). Add a com port to the device - mine comes up as COM8. The baud rate is 9600 by default, but can be changed with a special AT command, I set mine to 57600.




The range is nowhere near the XBees of course, however it is useful to configure PIDS  in the back yard etc - it's also nice and cheap.

There is some information in a multiwii discussion here. Also an interesting page with some useful technical info here.

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  • Hi all. I have my BT connected to my APM so that I can use my android phone to tweek the APM without a computer. Works fine. But when I try to connect to the BT using Mission Planner on my computer at Baud rate 57600, it will not connect, although the comp can see the BT com port...

    Any ideas? All the best for 2015.

  • Hi,

    I have just finished connecting this BT modul to my APM.

    It worked instantly for me.

    Thank you very much for this howto! ;)



    Youmight find this tool useful on configuring the modul ;)


  • Moderator

    @Druckgott Tried disabling firewall and anti-virus but still just get a black screen with a green cursor that I cannot type or paste anything into. It is definately the right com port.

  • Moderator

    @Monroe what do you need exactly? just a photo of the module and usb to ttl converter?

  • Ups...sorry!

    You need 5V data lines.

  • Hi Andrew,

    You can avoid all your troubles concerning 3.3V power line and data lines by simply doing this:

    LDO used is XC6206 ( ). It has case marking 662. You can unsolder it and shorten pads 2 and 3 ( see SOT-23 drawing from the datasheet ). Thus you can then simply power the BT with 3.3VDC from the autopilot.

    Hope this helps.

    Best regards


  • Switch of Firewall and Virus System I have the same problem with Putty

  • Moderator

    I have been trying to use Putty to change the baud rate of my bluetooth but cant seem to communicate at all? I can link to it whilst plugged into my laptop using my phone and send data to my laptop using bluetooth but cant send any commands out? any ideas?

  • Vernon,

    did you mean the pins betwwen the reset button and th I2C jack?

  • Thanks for your reply Vernon,

    I´ll give it a try.

This reply was deleted.