I have been using pixhawk for six months and I am very satisified with it. External usb&led adapter is a good option to download the dflogs from the plane because its not possible to reach the side usb port of pixhawk in the fuselage.

Last week I bought 3 new pixhawk boards from a reliable chinese vendor and 5 led&usb adapters but I could not make a connection between the boards using external adapters. When I connect it powers the board, pixhawk starts but no light on the external led and pc does not recognize the pixhawk itself via usb.
When I use the default usb port (side) pc recognizes the pixhawk.

First, I thought that one of the boards or adapters was broken but what is the possibility of 3 broken boards or 5 broken usb&led adapters at the same time?

Do you have any idea about what has been changed because I was able to use the led&usb adapter on my previous plane with another pixhawk from the same vendor?

Thank you.

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  • never, have I been able to get the external USB to work. We have managed to get the external LED working, but it appears to turn off the main LED on the Pixhawk.

    • I had a clone LED/USB that never worked reliably, but the 3DR one has worked flawlessly.

  • James,

    I've checked it pin to pin and saw that cable order is not correct in all 5 external led adapter.

    It took so many time but I corrected them and now they are working properly :)

    Thank you.


    • But now there is another problem.

      If I plug my dragonlink UHF reciever with PPM and RSSI cables with the board it does not power up from the external usb. If I unplug one of them it powers up with the external usb.

      So strange... It should not be this much complicated...

  • James,

    I've tried to check from the net. But I am not sure. Do you have any reference?

    These are 3 of my led adapters.



  • Admin

    @Onur BOY,

    I found that the wires on the external USB connector are so small that the voltage drop between the USB connector and the Pixhawk will reduce the voltage being sent to the Pixhawk to below 4.5 vdc which will result in the Pixhawk not booting up.

    Using the 3DR external USB connector I have been able to get the Pixhawk to boot up, but the attached PPM Encoder does not work due to the excessive voltage drop.



    • Thomas,

      Thank you for your interest.

      Actually when plug my usb cable to the external USB&led adapter, it powers up the board. But no usb data transmission. PC does not recognizes the pixhawk board. And the led on the external adapter does not working.

      I am confused.


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