RC input Voxl2 IO



  • We have received your IO Board, and will be using it solely to use the graupner radio and receiver.

    IO board led lights show normal running mode, and the radio is bound to the receiver.

    I cant see any RC input in QGC and 0 radio channels detected. There isnt a lot of info on setup of the IO board, am I missing something?


  • Dev Team

    Hi @McMason ,

    With graupner, it has generally not required setup, and if the LED is blinking blue on the VOXL2 IO board, then comms are working.

    Can you confirm you are using J3 (likely the black JST connector)?

    One way to troubleshoot that I use is as follows:
    https://docs.modalai.com/voxl-px4-developer-guide/#how-to-access-the-px4-shell-pxh

    Once you are running in the interactive shell, you can try:
    qshell px4io status
    and
    px4-listener input_rc



  • Hi Devteam, I'd like to echo this issue, as I'm having it too:

    I'm using the R9SX FrSky receiver with S.BUS output, hence I thought J2 is the appropriate connection. I've confirmed the receiver is bound and receiving the signal, and the blue PX4IO light is blinking correctly. I've tried both J2 and J3, but no dice. "qshell px4io status" in my case seems to indicate no RC connection is active, so the breakdown is likely either in how the signal is getting into the PX4IO or a setting with the PX4 rc_input "module" running in the PX4 stack perhaps?



  • @JoeC BTW, also, please check possible conflicting info between these wiki pages:

    1.) https://docs.modalai.com/voxl2-io-datasheet/ :The "Overview" image seems to suggest S.BUS is J2, while the "Connector Callouts" suggests S.BUS is J3.

    2.) https://docs.modalai.com/voxl2-io-user-guide/: The "RC Connections" section here shows J3 as S.BUS.

    I'm thinking J3 is the correct one for S.BUS inputs, given your response about the Graupner S.BUS being the black connector.

    -Joe



  • One more update:

    Possible problem 1: The FrSky S.BUS output is normally LOW and goes HIGH with data (does it need to be inverted?) Attached a file showing this.frsky.jpg )
    Possible problem 2: I found that I see the receiver S.BUS output signal with an o-scope when NOT connected also to pin 3 SBUS_INPUT_INV of the black connector. Upon connecting the S.BUS output to this pin, the voltage stays low, as if pin 3 on the PX4IO is pulling it down.


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