Alta 6 with FrSky D4R-II receiver?

Discussion in 'Electronics' started by Brian Merrill, Sep 28, 2017.

  1. Brian Merrill

    Brian Merrill New Member

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    Hi everyone. I'm trying to help a friend with his Alta 6 drone. He wants to use a FrSky D4R-II receiver and I'm trying to help by figuring out the connections. I'm new to this field and even with the reading I've been able to find I'm still confused if that receiver will work and how to connect it? The materials all assume you know the connector names and such...

    I can see how to upgrade the firmware on the D4R-II to have it use 8 channels and output CPPM which seems reasonable, but not sure about the drone connections.

    Anyone know any good reference material for this?

    Thanks,
    Brian
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Brian:
    I don't believe there are any reference materials published, but worse yet, I rather doubt that you are going to be able to get the D4R-II to work correctly. You might want to consider opening up a ticket by sending an email to Freefly Support (support@freeflysystems.com) and see if you can get answers though.

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  3. Brian Merrill

    Brian Merrill New Member

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    Hi Andy. Why do you think the D4R-II will not work correctly with the Alta? I'm a bit out of my field with RC vehicles so I've had to read up a lot lately. The D4R-II puts out a PPM signal which the Alta is supposed to be able to read. I know it's only an 8-channel receiver but that should be enough for it to work. I will see if the people I'm helping can talk to Freefly Support as they have been trying to do a lot by themselves and can probably use the help.

    Brian
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Brian:

    Good question. My concerns are that not all PPM signals are created equal -- and thus I would proceed cautiously, just in case the signal timing is different. PPM is a system where inter-pulse gaps are used to determine pulse-widths (and therefore the proportional signals) for successive channels. I would certainly try it. The channel mappings are published for the ALTA 6. See page 39 and following.

    My concern would just be that if you only have eight channels, the receiver will only be sending eight channels of PPM to the Synapse flight controller. I'm not sure what the Synapse flight controller will do for channels 9 and 10 if there is no corresponding PPM pulse.

    So if it were me doing this, I would certainly try assigning the channels 1 to 8 to the flight critical functions. You probably do not need velocity and climb rate clamp for initial testing so leave those channels unassigned (presuming there is an "unassigned" setting). But I would not fly higher than a few feet AGL for initial testing just in case the PPM timing is on the very thin edge of working -- it will minimize the damage in case something, somewhere, is not quite right.

    I've been working with computers and RC controllers for too long to completely trust that compatibility is ensured, I suspect! :)

    Hope this helps.
    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  5. Brian Merrill

    Brian Merrill New Member

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    Hi Andy. Thanks for the detailed response. That helps a lot and I'll see what I can do to get them to use a receiver with more channels.

    Brian
     

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