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  1. Fishie

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    Hey all,

    I use a power wheelchair and just received my Phantom 4. I've read a lot about people insisting or being paranoid about compass calibration around anything that is metal. Founded or not I have no other choice since I cannot walk and my chair is one huge piece of metal and perhaps some EMI from the electronics.

    DJI's tech dept. says The wheelchair could cause issues but said that if I get a successful calibration showing in the App then I will be fine. Has any one's App shown a successful compass calibration but in flight their quad acted erratically?

    So...short of bringing someone else to a flying site which is not likely, what are my other options? I've considered everything from placing the P4 on a small spinning lazy susan and tying a long string to it and driving around in a large circle, OR creating a small motorized lazy susan, OR don't they sell lazy susan's for microwaves that turn on their own like a kitchen timer?

    How quickly do you have to spin around? If you don't spin around fast enough will the P4 time out??

    Thanks for helping me solve this dilemma!

    Ideas??

    Chris
     
  2. WWK888

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    As long as you are flying within a few hundred miles of where you calibrated you should be good. So first I would try calibrate and see what happens. If you get no error messages you are fine. If you do, have a friend or neighbor help you calibrate it before you leave to go flying.


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  3. Fishie

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    Thanks. DJI Tech Support said to recalibrate at every unique location.

    I haven't activated yet but likely will reluctantly pay for a 6 or 12 month insurance just in case I do run into issues. With a disability, especially muscular dystrophy like me.... life costs more...special modified car, wheelchairs, hiring helpers, etc.....
     
  4. WWK888

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    Some people here including myself feel that calibrating too often can do more harm than good unless you are hundreds of miles away from the last calibration.


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  5. Fishie

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    I guess I will try it and find out. Thank you.

    Since I am new to this forum...what is the rationale that it can do more harm than good? How could it be a bad thing unless you recalibrate in a new location with lots of RF or metal structures? If so, that makes sense.
     
  6. Dirty Bird

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    The Phantom depends on an accurate compass calibration. Each time you calibrate there is the possibility of introducing error or obtaining a bad calibration. My Phantoms have flown several million feet all about Maryland. The compass on each has been calibrated once. Only if I travelled an extended distance (100+ miles) would I calibrate again.

     
  7. grizgrin

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    Do you ever check your calibration? Would there even be a way to do that? Or would it just be a matter of flight being weird as your indicator the cal was off?
    My first drone is on the way, so please forgive a pissibly stupid question.
     
  8. John Locke

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    Fishie, what dirty bird said. Most of us with millions of feet distance under our belt have learned it's not necessary to calibrate compass at each location. Theoretical it makes no sense, and in practice it's the least risk. Many of the DJI help line folks are ignorant, there's many examples of that in this forum.

    There is a GO app screen that shows a graduated bar, green for good and red for bad for compass status. The IMU status is on a neighboring tab in that same screen. You can use that each time to confirm all is good, but I rarely do this with my P4 anymore because you will get screen dialog if something goes wrong. But checking this is easier and quicker than recalibration each time if you want peace of mind.
     
  9. Dirty Bird

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    If the Phantom recognizes there is a compass calibration issue (ie you are on a park bench with a magnetized metal structure beneath) you get an on-screen pop up alerting you. The rear lights also flash yellow. I have had this happen when launching from a pier or bridge. I just move the Phantom until the warning is abated.

     
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  10. Fishie

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    Wow thank you all for the tips and advice!

    So the compass heading must get locked into the memory??? The compass works in sync with the GPS since they work together to give the drone the right orientation? Removing the battery retains these settings I suppose?


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  11. Fishie

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    So turning on a calibrated quad while my wheelchair is near won't reset or jack up the compass settings?


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  12. Dirty Bird

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    Correct. Many other settings are stored also when the battery is removed. RTH altitude/behavior, low battery alerts, camera settings, front lights, etc..

     
  13. Dirty Bird

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    Only if your wheelchair is extremely magnetized. Any relation to Magneto? You're probably OK otherwise. ;)

     
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  14. John Locke

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    Yes, it's very true what DirtyB said. And you can confirm that by having someone use a cheap mechanical compass and test if your chair affects readings to North when the chair is close.
     
  15. Fishie

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    Or perhaps my iPhone compass App for magnetic North?


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