Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

How flat is flat ?

Discussion in 'Pro/Adv Discussion' started by Ceredigion, Jul 1, 2015.

  1. Ceredigion

    Joined:
    Jun 24, 2015
    Messages:
    5
    Likes Received:
    1
    Hi everyone - first post - UK flyer !

    I'm about 2 weeks into my P3P, having spent 18 months with the Phantom 2 Zenmuse and I'm mightily impressed. I flew it straight out of the box after installing the latest firmware and it was perfect. I forgot to calibrate compass or IMU but like I said it flew and filmed perfectly.

    Yesterday in my haste I switched the bird on without removing the gimbal lock and promptly received a warning message saying something like "excessive force on gimbal". I realised and switched it off within seconds. I'm hoping that DJI factored in this possibility and will have programmed an abort warm-up routine for the gimbal in this situation ?

    Anyway, I flew it later last night and again today and my horizon is tilted and the camera is also looking slightly to the left. I'm hoping that I simply need to re-calibrate compass and IMU and all will be well.

    I'll try the sheet of glass over the motors test to make sure I'm calibrating the IMU on level ground and have downloaded separate spirit level apps on my iPhone to measure the flatness, and they seem to be in agreement with each other about what is flat which is encouraging.

    My question is then..... How flat is flat ?The table I'm thinking of doing the calibrating on is measuring about 0.4 degrees off in both planes which equates to about a sheet of paper. Is this flat enough or should i place a couple of sheets under the skids to get the level to 0.0 on both planes ? Is this even an accurate way to ensure "levelness" ?

    Thanks in advance guys.
     
  2. happydays

    Joined:
    Jul 5, 2013
    Messages:
    1,858
    Likes Received:
    663
    Location:
    Warrenpoint, Ireland
    I wonder about iPhone level apps. I have a 6 - and with the lens sticking out of the back, it can't lie flat on its back. With the buttons on each side, it can't be used that way either. The only way it can be used is on its face, and then you can't see the screen. Just sayin' like!
     
  3. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,683
    Likes Received:
    5,713
    Location:
    Amory Mississippi
    Welcome to the forum Ceredigion :)
    Was involved in testing this with the P2 and am interested in what all have to say about this with the P3 !
     
  4. Ceredigion

    Joined:
    Jun 24, 2015
    Messages:
    5
    Likes Received:
    1
    Thanks Guys ! I'm on an old Iphone 4s so the camera doesn't feel like it protrudes at all. In fact it's that corner ( top right of phone facing upwards ) that i need to prop up with a thin piece of card to get it to 0.0 on both planes. Obviously a proper digital level would be the preferred option but they seem to be £20 upwards so was just wandering if this is a "near as dammit" method ?

    P.S has anyone else turned the bird on with the gimbal lock still in place ?
     
  5. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,683
    Likes Received:
    5,713
    Location:
    Amory Mississippi
    Level table.jpg Cheap but dead on ! Only 1 1/2" across :)
     
  6. Buckaye

    Joined:
    Aug 24, 2014
    Messages:
    1,557
    Likes Received:
    420
    Location:
    Orlando
    My case takes care of all of those leveling problems.... buttons are flush on the case... and the back actually has 4 little legs (for lack of a better word... more like bumps)
     
  7. happydays

    Joined:
    Jul 5, 2013
    Messages:
    1,858
    Likes Received:
    663
    Location:
    Warrenpoint, Ireland
    I'm naked at the moment. My phone, that is, not me personally...
     
    dirkclod likes this.
  8. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,683
    Likes Received:
    5,713
    Location:
    Amory Mississippi
    Thanks for that happy :eek:
     
    happydays likes this.
  9. Ceredigion

    Joined:
    Jun 24, 2015
    Messages:
    5
    Likes Received:
    1
    Out of interest then dirklod - how does a free spirit level app compare to your bubble level ?
     
  10. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,683
    Likes Received:
    5,713
    Location:
    Amory Mississippi
    Never compared em bro !
     
  11. mad in nc

    Joined:
    Dec 16, 2014
    Messages:
    534
    Likes Received:
    214
    Location:
    North Carolina US
    I would try the paper to 0.0, advance IMU cal then look at the Horizon via FPV If still off a little bit, shim the low side up with a couple of business cards to make an attempt on the flattening of the horizon view. I don't know how much can be raised before the IMU try's to compensate. Re gimbal - yes.... Thats why have the 6 in ribbon on it to remind me..
     
  12. Ceredigion

    Joined:
    Jun 24, 2015
    Messages:
    5
    Likes Received:
    1
    Well..... you know..... I know I'm new her and stuff but .... Get to it man !! ;)
     
    dirkclod likes this.
  13. ianwood

    ianwood Taco Wrangler
    Staff Member

    Joined:
    Jan 7, 2014
    Messages:
    4,932
    Likes Received:
    1,802
    Location:
    Lost Angeles
    For calibration, you want it to be extremely level. Unless you know your phone shows perfectly level, get a simple spirit level off of amazon. Put something flat across the 4 motors and shim the landing gear until it's perfect.

    For take offs, a level surface is good but not necessary.
     
    RyanK likes this.
  14. Ceredigion

    Joined:
    Jun 24, 2015
    Messages:
    5
    Likes Received:
    1
    Thanks mad in nc, did it have an affect on your gimbal/levelness when you made the same mistake as me ?
     
  15. mad in nc

    Joined:
    Dec 16, 2014
    Messages:
    534
    Likes Received:
    214
    Location:
    North Carolina US
    not that i noticed.....
     
  16. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,683
    Likes Received:
    5,713
    Location:
    Amory Mississippi
    Ya Got Me.jpg Ya got me :D
     
  17. taroh

    Joined:
    May 4, 2015
    Messages:
    238
    Likes Received:
    48
    Location:
    Yokohama, Japan/Taichung, Taiwan
    Differs to the yaw sensor, roll & pitch can be always corrected by the gravity on this earth, ok to startup at not so flat place, in principle. Otherwise, cheap gyro always drifts (few degree per second), and flips over soon. And using mobile device, its gyro is almost the same precision as P3's. :) Do not be too much nervous. Human eyes are very exact, if you feel it's horizontal, that'll be under 1-2 degree.
    BTW "gimbal overload" message is shown after 1.2.6 firm upgrade. I saw when I forget to remove the gimbal lock part (I think it's not detected before). If you remove the plastic part but the message is shown, any fixing on gimbal motor(s)???
     
  18. Fplvert

    Joined:
    May 28, 2014
    Messages:
    1,559
    Likes Received:
    708
    Location:
    Southern Idaho USA
    Doing the IMU calibration the bird does need to be as level as possible. It's also important to isolate any vibrations while the calibration is in progress.

    After IMU, calibrate the gimbal and your camera should be re-centered and level. If not, you can manually adjust it in the app.
     
    dirkclod and Steve Moore like this.
  19. AHill

    Joined:
    Oct 10, 2013
    Messages:
    227
    Likes Received:
    23
    A way to check if level is working correctly is to take a reading with it and then rotate it 180 degrees and see if it still is reading the same.
     
    Fplvert likes this.
  20. snowghost

    Joined:
    Feb 13, 2015
    Messages:
    1,058
    Likes Received:
    213
    Location:
    SoCal, USA
    I tested a couple iOS apps on my old iPhone 5s and they were all off compared to a real level. Not going to bother with the 6 +