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Compass calibration and degaussing

Discussion in 'Phantom 2 Vision Discussion' started by Bigbells, Mar 6, 2014.

  1. Bigbells

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    "If the mod value is below 750 or beyond 2250, you should......................”

    That is language from the PT2 software, concerning the "Compass Raw" readings.

    That value has read ~2650 from the minute I removed my new Vision from the box, with the compass module already attached to the landing skid, which was also already attached. There is no improvement in that number when I calibrate the compass, and no improvement in that number when I run the IMU calibration.

    The instructions for degaussing say to orbit the compass with a magnet on "two horizontal axis and one vertical axis". Can anyone explain the 3 different directions in which this orbiting should be done?

    I figure the magnet I should use is the magnetic screwdriver shipped by DJI with the Phantom. Can't figure out why DJI says not to use a magnetic screwdriver close to the compass module, then ships the Vision with a magnetic screwdriver in close proximity to the compass module.
     
  2. Pull_Up

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  3. Bigbells

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    Thanks much! If I wanted biceps as big as Colin's, would it hurt when my present ones were reduced? Nyuck nyuck nyuck.

    2 things:
    Since the current compass error is not so large that I can't fly GPS, I think I'll try getting the Phantom off the concrete floor where I've done previous calibration and see if I can get a better calibration.

    I'm thinking the magnetic screwdriver may well have enough magnetic force to degauss the compass module.
     
  4. Pull_Up

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    I'm thinking you really need to read up on calibration! ;) Definitely away from concrete, structures, underground pipes, etc. Nice big field. Once you get a good calibration you shouldn't need to do it again unless something changes on the aircraft, you fly far away from the otiginal calibration site or the aircraft stops flying stable and true.
     
  5. Bigbells

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    In my current geographical location with current driver's license status, combined with the "no trespassing" signs on suitable areas within walking distance, it is virtually impossible to find an ideal location for compass calibration. I can fly OVER such areas but can't set foot ON those areas. There are parks and such within driving distance if and when I can get a ride. This is the greater NYC area, not a whole lot of places where there are not big metal structures above and under the ground. You country folks don't understand. :lol:
     
  6. Pull_Up

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    <tunes up banjo>
     
    jryser likes this.
  7. slicknet

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    Pull-up, the link you put-up from DJI reminds me how much I miss Colin. I felt more connected to DJI when he would create videos with issues and instructions for the Phantom.
     
  8. Hiway

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    <jerks head around at the sound>

    Appalachian cat gut box... songs of my people; strum it feller!
     
  9. Bigbells

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    I got my Vision up off the rug-covered concrete floor by putting it on a wood-and-fabric footstool. Then I connected to the PT2 software and voila!... the "compass raw mod" reading is now around 875 instead of 2650. After fresh IMU calibrations, the copter insisted on a new compass dance when I went outside. Thanks for the beating with the 2 X 4 to make me think of the fact that just maybe, the concrete floor of this 5th-story apartment would have an effect on the compass.

    When flying, the GPS hold is not quite as precise as I'd like to see it, even with 12 satellites. A little bit of circular hunting, and the Vision also is in the habit of tracing an inverted "J" in the sky when I release the sticks before it settles on a spot to hover... I've gotten used to it but I'm hoping for a suggestion on eliminating or reducing those peculiarities. Calibrate the sticks again?

    My other question, about programming the 3-way switches on the remote control, I'll post as a new topic.