Dead Gimbal ?

Discussion in '2 Axis Gimbal' started by Jon Ford, Jun 4, 2013.

  1. Jon Ford

    Jon Ford New Member

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    A big hello to all from southern France!
    Having assembled and flown my cinestar 8 a few times I felt ready to use the 2 axis gimbal. Unfortunately when I connected it up...nothing happens. It's strange as when I had tested it on the bench a few months ago it did work.
    I could be doing something very stupid here...In fact that's more than likely. Is there a way to disable/enable the gimbal? If there is I can't see it. Fingers crossed for something simple.
    thanks in advance
    Jon
     
  2. Brad Meier

    Brad Meier Active Member
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    Hard to tell what's going on without being there. How are you running power to the gimbal?
     
  3. Jon Ford

    Jon Ford New Member

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    It's being powered through the FC. I did measure 5v coming out of the FC but I don't know about the third (orange) wire.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Can you also post some images showing the wiring to the servos etc, Jon, and clarify a bit further? Is there any power going to the servos? Are you using Radians to stabilize or an MK FC board? It sounds like it's not even getting any power.

    Andy.
     
  5. Jon Ford

    Jon Ford New Member

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    Hi Andy Here's a pic of where the roll servo is plugged in. The nick is on the opposite side of the FC. I measured 5v coming off the FC so it does have power. I'm not sure abot the signal (orange wire) though. I'm not using Radians......yet.
    thanks
    Jon
     

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  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Jon: Well, that certainly does seem to be the correct connector for the roll servo (SV3) according to the diagram at http://www.mikrokopter.de/ucwiki/en/FlightCtrl_ME_2_1 (the diagram needs to be rotated 180 degrees to match the orientation of your image.

    The problem that there's no easy way to debug a servo output without access to an oscilloscope so you can see whether there an pulses being output on the orange wire.

    If you connect up MK Tool to the FC, and use the 3D button (to get the 3D replica of a copter) does the replica track the motions of the FC?

    I'm just grasping at straws to try and find a way to do some basic diagnosis here....and the first thing I suspect is the Flight Control board isn't behaving the way it should....so isn't driving the servo outputs correctly....

    You might also want to check out how to use MK Tools' "Scope" feature and just get a sense of whether the accelerometers are working ok.

    Andy.
     
  7. Jon Ford

    Jon Ford New Member

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    Thanks Andy. I tried the 3D option and it seems to track the copter perfectly.
    I have to say I don't really understand what I'm looking at with the scope feature but to describe what I saw; The upper line didn't do anything when I moved the copter but the lower line did move very slightly and displayed some short lines when the copter was moved. Maybe there is something very basic that I've overlooked, my thought being, I'm virtually computer illiterate, so anythings possible.

    Jon
     
  8. Adam Paugh

    Adam Paugh Distributor

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    Hello Jon,

    With the kopter all powered up and your transmitter on, have you calibrated the gyro with the stick command from the transmitter (full throttle/full left rudder)?

    Greetings,
    Adam
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Adam raises a very good point: Have you also calibrated the accelerometers? This is a one time thing....the calibrating the gyros that Adam mentions is once each flight before you start the motors.

    You might find this web page helpful: http://www.mikrokopter.de/ucwiki/en/Mikrokopter-Get-started

    Andy.
     
  10. Jon Ford

    Jon Ford New Member

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    Hi Adam
    You're spot on! It works!!! Thank you!
    I didn't know I had to calibrate the gyro to get the gimbal working....well I do now.
    Many thanks again for all your help

    Jon
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The reason you have to calibrate the gyro is otherwise the FC board doesn't know how to move the gimbal to maintain the right angle with respect to the ground. :)

    Andy.
     
  12. Jon Ford

    Jon Ford New Member

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    Yes, now you say it, it makes complete sense.
    Now I'm worried I haven't calibrated the accelerometers :eek:. I followed your excellent dvd to the letter, plus it flies great! I'm going to double check anyway.
    thanks
    Jon
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Thanks for the kind words about the DVD, Jon -- now you've got me worried -- I could have sworn I covered calibrating the ACC...please know if I did not! :)

    Andy.
     
  14. Jon Ford

    Jon Ford New Member

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    Don't worry, I just checked on the DVD, you did cover calibrating the ACC. That's good news for me as this means I would have done it too.:) Thanks
    Jon
     

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