FPV Cable for SJ8 does not work

Discussion in 'SJ8 Series' started by nianeko2, Aug 28, 2018.

  1. nianeko2

    nianeko2 Member

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    I bought a Original FPV Cable for SJ8 at AliExpress, but did not work.
    I found pin connection of this cable is wrong.
    This cable's USB-C pin No. is
    VBUS: A4 〇
    GND: A5 ×
    GND: B3 ×
    RX: A8 × /A8 must be CVBS
    VCC: A12 × /A12 must be GND
    DET: B12 × /B12 must be GND
    CVBS: B10 ×
    Only VBUS is correct. This cable is really SJCAM original?

     
  2. Sulev Svilponis

    Sulev Svilponis Elite

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    You mean, the labeling is wrong?
     
  3. nianeko2

    nianeko2 Member

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    Label and line is same color, so pin connection should be fixed.
    But after buying this, we only can change label. :(
     
  4. Sulev Svilponis

    Sulev Svilponis Elite

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    AFAIK SJCAM used white and yellow wires for FPV already for SJ6 and SJ7 cameras. In cables for those cameras the yellow wire is labelled as AV-out and the white one as PWM (should be connected with the ground). So there is not much surprise, that SJ8 uses also white and yellow wires, and one of them has to be connected to the ground.
     
  5. nianeko2

    nianeko2 Member

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    OK, if used FPV for SJ6 or 7 and not read the label for SJ8 may be not so surprised. ;)
     
  6. Damian Holt

    Damian Holt Moderator

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  7. Sulev Svilponis

    Sulev Svilponis Elite

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    Last edited: Aug 30, 2018
  8. Damian Holt

    Damian Holt Moderator

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    Not sure to be honest, I don't use the cables so couldn't tell hence the "potentially"
     
  9. nianeko2

    nianeko2 Member

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    At that time I tested FPV cable with new fw 1.2.6.
    And found after using FPV mode can not shut down, without pull off battery.
    So 1.2.6 still has some bug. But of course no bug camera is impossible. ;)

    I found this FPV cable's "GND" is not connected to camera's ground.
    So if connect external power to "GND", may cause some damage to the camera.
     
  10. Sulev Svilponis

    Sulev Svilponis Elite

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    How did you found this? Opened your camera and did some measurements with a multimeter?
     
  11. nianeko2

    nianeko2 Member

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    This is USB type C specification.
    You know mini and micro USB spec. No.1:Vbus, No.5:Gnd
    Type C is No.4,9:Vbus, No.1,12:Gnd
    And SJ8 attached USB cable's Gnd is No.1
     
  12. Sulev Svilponis

    Sulev Svilponis Elite

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    Are you sure, that USB type C specification specifies that A5 and B3 can't be connected with the GND from the camera side?
    AFAIK the specification does not specify function of all the pins. Producers have some freedom to play with.
    I suppose that No.4,9:Vbus, No.1,12:Gnd are reserved for charging/external power, but the FPV cable is not meant to be a charging cable.
     
    Last edited: Aug 31, 2018
  13. nianeko2

    nianeko2 Member

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    If do not use this FPV cable as a charging cable, the camera is safe,
    and SJCAM lost the chance to sell another one. ;)
     
  14. Sulev Svilponis

    Sulev Svilponis Elite

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    I think that those GND-s and the VBus of this cable are NOT for charging the camera, but to provide GND and VBus to connected device (FPV signal transmitter for example).
     
  15. Scott Pritchett

    Scott Pritchett New Member

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    I couldn't find the AV cable in stock in the USA, so I attempted to make my own from a short male-male type C cable and a female break-out board.

    Ground and VBus work fine to power the camera, but A8/B8 don't work for composite video out. I even used my oscilloscope and verified that none of the pins have video on them in "FPV" mode. I'm guessing the real AV cable has a pull-up or pull-down or pins connected together to tell the camera it's connected and enable composite output.

    Does anyone have more info on this? If you have an AV cable, could I ask that you ohm out the pins and see if any pairs are connected or connected via resistors?

    Thanks,
    Scott

    Meanwhile, I'll be ordering a cable from China...
    PS. My camera is running 1.2.4 firmware.
     
  16. nianeko2

    nianeko2 Member

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    What is your male-male type C cable?
     
  17. Scott Pritchett

    Scott Pritchett New Member

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    Ah, good point. Perhaps this cable only has power connections. The notes seem to indicate that it should work for data transfers, but that doesn't necessarily mean it has all wires connected. I can't post a link, but it's from Amazon with the following description:
    USB Type C to C Cable(3A), CableCreation 1ft Short USB 2.0 Type-C Cotton Braided Fast Charge Cord, Compatible MacBook(Pro), Nintendo Switch, Galaxy S8/S8+ etc, 0.3m/ Space Gray
     
  18. Scott Pritchett

    Scott Pritchett New Member

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  19. Scott Pritchett

    Scott Pritchett New Member

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    I got a male Type-C breakout board and can affirm that just connecting A1 to ground and A8 to video works fine for AV-Out. No other connections are needed. The cable I was using before must not pass A8.
     
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  20. Sulev Svilponis

    Sulev Svilponis Elite

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    Without having the camera and without any testing I suppose, that the SJ8 USB-C FPV cable has following pinout: SJ8pinout1a.jpg

    So the FPV should work from A8 and B1 too (any GND should do instead of A1). Or from B8 and B12.
     
    Last edited: Sep 23, 2018

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