Tarot 2D Gimbal Random Movements on Power Up

I have upgraded my Iris to an Iris+ and just plugged in the Tarot gimbal for the first time using the instructions on the 3DR site.  However, on power up the gimbal with the GoPro H3+ is moving randomly in all directions and the "Tilt" know on the FS TH9X does not appear to be working.  The gimbal LED is flashing blue which indicates that it has initialized properly.   I have read that there are gimbal calibration instructions available as well as a newer version of the firmware (v 1.5 I believe).  Since this gimbal was shipped with an older Iris should update the firmware immediately or should I try to find these calibration instructions first?

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  • MArk, from the 3DR-recommended settings file (save it as yourname.bgsc to be recognised by the utility):


    (Sorry, I can't see a place to attach the text file directly. Just paste that into notepad or vi or 'cat > 3DR_IRIS_Settings.bgsc' etc.)

    The gains they use are slightly conservative but in this case there's no "performance" to worry about, it's all about enough gain to move as expected and NO SHAKE which is achieved just fine with these settings!

    Just one other thing occurred to me, the "chip" on the back to the gimbal needs to be level and motionless. Have the gimbal off the bird, or like I did, have an assistant (sexy assistants work better for this I find) hold IRIS above the corner of your desk, then you can hold it steady with one hand and click Calibrate with the other. Sexy assistants like geeky motor control software with a graphic visualisation element.
    • Hi Chris,

      It has been a totally frustrating evening.  While I did discover that I had the gimbal control board wired up incorrectly (orange wire to top pin, not middle) I am still having problems configuring this gimbal.  The symptoms are:

      • When I turn the Tilt knob just slightly on the TX the gimbal move dramatically down and then starts jittering
      • When I roll the Iris+ (left tp right) the gimbal moves violently to the left.  It does not do so on the right

      I have calibrated the sensors at least a dozen times and loaded the above configuration as many times.  So I am lost right now. Perhaps it is a hardware problem?

      Finally, I am also at a loss to find a sexy assistant! 

    • Mark,

      There should not be any wire connected on any middle pins!


      See the above URL for a photo from the errata page.

      Cabling issues could easily be fatal, but also make sure you have the bottom right "mode" or whatever (sorry, going form memory here) set to "STICK POSITION" or some such, not anything with "rate" in it. Makes it all suck fast when that happens.

      Hope this helps.  Sorry if I was unclear in my first description of the wiring fix -- can't check it as I'm at work and get a guilty feeling spending time on fun stuff after a few minutes.  :-)


    • Hi Chris,

      I checked the Pixhawk wiring and it is connected to the top and bottom pins so I think that was all right.  The orange lead is connected to the middle pin on the top row on the Tarot control board and the brown lead is connected to the last pin the second row as illustrated in the upgrade kit.  So I think we are all right here as well.

      I finally removed the Tarot from the Iris+ and performed a calibration of it sitting flat on the table with the lens pointing up (skyward).  It appears to have calmed it down a bit, but the gimbal still seems to "jerk" at random intervals.  Also both motors are vibrating constantly so I am sure I will have to mess with the gains.

      Don't lose your job over this!  But I want to let you know that I really appreciate your input.  Now get back to work!! :)

    • After tweaking the Roll and Pitch gains in ZYX-BMGC I think I finally have the Tarot 2D gimbal moving properly and smoothly.  But my last challenge is getting the FrSky TX knob (CH 6) to control the tilt.  When I turn the knob ever so slightly clockwise the gimbal does tilt but stutters a lot and then finally rotates the camera 90 degrees.  When I move the knob counterclockwise the gimbal moves randomly but finally settles in and points the H3+ full forward.  I played around with MP trying to get it working but every parameter I changed had no effect.  Does anybody have any suggestions?

    • Couple things come to mind Mark.

      Sort of obvious but make sure you don't have the gimbal fighting against it's own ribbon cable.  Seems every time I set it up and get ready to turn it on, I notice it's managed to get a full turn on the horizontal axis and I need to give it a rotation to free up movement.

      The "stick position" not "rate" thing, on the bottom right of the software, is key.  All sorts of weirdness, I ended up out on a "job" (Community Easter Egg hunt) and my go pro went into the "pointing down" position when I moved the tile knob...  I had not gotten that set right.

      And why is that?  Because in my haste I apparently did not write the settings to flash before exiting the last time; so it didn't "stick".  So yeah, silly but really is an issue, not flashing the settings, last thing before you say it's done.  And in fact, a routine I am adopting is "power cycle then test" at the end of my "night before" prep or "before the ride" etc.

      Hope this helps.  The Tarot seems to me to be a pretty straightforward piece of hardware but the manual and general magic quality of it means the assumptions don't always hold true, and I personally needed to "respect it" more to make sure I just followed the rules...  The Calibrate thing bit me hard because it's not in the instructions.  The Internet saved me on that one. :-)

      Good luck,


    • Success!  After a few evenings of frustration I have the gimbal tilt operation sorted out.  I discovered that after I calibrated the radio in MP  - including turning the CH6 knob a few times clockwise and counterclockwise - I can smoothly control the tilting of the gimbal.  While I was at it I calibrated every switch and stick on the FrSky TX.  I still have to work on the range for the knob but I am satisfied that I can control the tilt.  So success at last!  Now off to the field for some flight time!

      Thank you all for your patience and kind input.


    • Glad I found this.  Had the same problem after installing a new Tarot control board.  The radio calibration fixed the tilt dial shaking issues!

    • Yes, I have learned that when you calibrate anything with the Iris+, it must be done thoroughly. Happy flying!
  • Not sure if there is an undocumented hardware pin short or something... There is not much documentation just the bare basics.

    I also have something else I learned today... I have been setting my Tarot to do 0 to -135 degrees, because it can, even though the IRIS settings provided by 3DR do 0 to -90. Well today I was playing with follow me, following my Traxxas Summit 1/10 with the Nexus tablet on board... Which got a few more people gawking than normal even, hehe... but I noticed the camera angle was way off and the way it was on, then increasingly wrong makes me thing it's that extra 45 degrees I've given the range coming up as an error in the maths where at one point they align, otherwise the camera position is off by progressively more the farther from the centre of travel (According to the software/pixhawk).

    So I shall be reconfiguring mine too! But not going to give into the temptation to press that nasty Calibrate button. :-) Otherwise I may need some more help fingering out this behaviour.

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