• Hello Marco,

    I'm new to Pixhawk and I want to "recycle" my Mikrokopter frame. So I'm trying to enable the mkblctrl option in Pixhawk. I need to understand more in detail the steps to do. I'm not very experienced in managing a linux system by console commands, but I remember stuff from old MD-DOS time.

    Up to the moment, I'm able to connect to the nsh and get a prompt from Pixhawk. I can cd to fs/microsd/APM/ and create a file here. My question is: What kind of file must this be (extension needed?) and what shall it contain?

    After creating this file (mkblctrl_x in my case), what shall I do? Reset the Pixhawk? How can I check if the mkblctrl driver is running?

    Reagards, Frank

    • Hello Frank,

      at first you should to the basic setup of your Pixhawk.
      Frame, Radio Calibration and Sensor calibration.
      Then turn the Pixhawk off, eject the microsd card, and put it in the cardreader and stick it into your computer. Go to the card, and go into the APM directory on it.
      Here you create a empty file named mkblctrl_x (without any file extension). On windows you can open your notepad, and then go to save file as - here you go to the APM directory of your card, and enter mkblctrl_x as filename.
      Nor you are ready. Eject the card from your pc and put it back into the pixhawk.
      After powering on (boot) you should see the green led on all blctrl escs on - then the driver is working and talking to them.
      If you get solid red leds, please check your cables to the escs.

  • Anybody?

    Please, I need information to upgrade my MK into a Arducopter, PX4 or Pixhawk! ?¿

    I want to know if i2c ESC have good performance with this electronics.

    Best Regards,


    • Hi,

      i am using PX4 Flightstack and ArduCopter for almost one year with the Mikrokopter BL-Ctrls (i2c) with absolutely no worries :)

      If you have a PX4 or Pixhawk, then you are on the lucky side. The BL-Ctrl ESCs are supported by ArduCopter in the current Developer Version. You can easy replace the Mikrokopter Flight&NaviCtrl with a Pixhawk or PX4 Board.

      Small short instructions to get this ESCs working:

      Mikrokopter ESCs have to be connected I2C Bus on Pixhawk/FMU.

      Arducopter Mode:
      To enable mkblctrl startup add a /fs/microsd/APM/mkblctrl file
      In this configuration the ESCs must be ordered in the same order as the ArduCopter is numbering them.
      In this Mode all Frametypes of ArduCopter are supported.

      Mikrokopter Mode:
      To enable Mikrokopter native Frame Addressing (Order) support:
      For X Type Frame add:

      For + Type Frame add:

      With Mikrokopter Frame Addressing, it is very easy to convert a Mikrokopter to ArduCopter. Just replacing
      the Flight-CTRL against a Pixhawk, and your are done after initial Setup.

      In Mikrokopter Mode there are only X and + Type Quadro, Hexa and Octo Frames Supported.
      In Mission Planner the right Frame have to be set.

      There can be only one startup File on the SDCard (mkblctrl, mkblctrl_x, mkblctrl_+)


      A short video of a Quadrocopter with Pixhawk and ArduCopter Firmware flying, can
      be found here :

      • Hi Marco.

        With ArduCopter 3.2.1, almost immediately after it boots up, my motors all start running at a medium-low speed, even before arming. They never change speed, and adjusting THR_MIN has no effect (although I'm not sure I successfully adjusted it). Powering down the Pixhawk also stops the motors.

        Any idea what's going on? Thanks!

  • Hi, the MK BLs are not very good with PWM. They use the built-in oscillators in the atmegas and they are not good. For I2C it doesnt matter but for PWM it means inaccurate throttle. You can try calibrate their oscillators and/or put SimonK firm on them, if you know how.
    If you get other ESCs, pay the extra money and get some with chrystal oscs. Regards, Soren
  • Developer
    If you use the PX4 controller, some support for mikrocopter i2c ESCs has been added see

    This will probably work with the new Afro ESC from hobbyking as well, as that also supports i2c (but needs to be verified)

    Though it pretty new stuff and i'm not 100% sure if its end to end yet.
  • 3D Robotics

    I'm not familiar with the MK ESCs, but APM only supports standard (PWM) ESCs. 

This reply was deleted.


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