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Caution Compass Calibration Danger! Motors Started Turning!

Discussion in 'Inspire 1 Discussion' started by Kirk Pleasant, May 17, 2015.

  1. Kirk Pleasant

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    They say experience is learning from our mistakes.. I gained some experience today!

    I checked my compass before flying and it was about 1450. The Inspire started having trouble holding position in an 8.5m/s wind. I checked the compass again and it was down to about 1250. I decided to calibrate the compass. I did the compass dance, first flat - it took almost 720 degrees of turn to make the light change green, I then did the turn with the nose pointed towards the ground. As soon as I got the flashing green light on the tail the motors started randomly powering up to full power!

    I was standing holding the Inspire with the props randomly spinning away (sometimes at full power) wondering if I was going stay there holding it until the battery was dead. I finally managed to get to my controller (after saying many bad words!) and send the kill signal to the Inspire.

    What I learned was NEVER calibrate the compass with the props on.

    I was lucky that I was careful of how I was holding it …just in case the props started. And they did!

    Be careful,

    Cheers
     
    #1 Kirk Pleasant, May 17, 2015
    Last edited: May 17, 2015
    jon b and Mete like this.
  2. Ferdi

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    Whoa!!! That is nuts! Glad you dodged that one... The way I calibrate I'd have lost some fingers :eek:

    Thanks for the heads-up!
     
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  3. artsribanpot

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    I always have that thought it would do just that with my luck (bad one). Kirk, with that happened to you, I now will put the props on after compass cal. Thanks for letting us know that happened.
     
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  4. turbodronepilot

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    Good save Kirk!!
    Glad you kept your cool!!
    Thanks for sharing..
    Wonder if since the light didnt come on at just past 360 its a sign a false start up is possible and then we could cancel the calibration and start over..
    I don't like taking my props off so I'll just be on the look out for this to happen..
     
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  5. Ian Fraser

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    Did you report this to DJI and send them your Log Files?
     
  6. The Editor

    The Editor Moderator
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    Something isn't right here.
    The motors cannot start without a verified CSC command from the transmitter which, once interpreted by the receiver as full stick throw is decoded by the flight controller to initiate idle to the motors via the esc's.
    There is too much in the chain of command that must be logically true and verified for them to randomly start!
    To my knowledge, there has NEVER been an instance of an uncommanded motor start. The esc's must be armed before this can occur.
    You need to give more details of exactly your actions leading up to this including the end of your flight prior to this occurrence.
     
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  7. Kirk Pleasant

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    Well they have now..
    Landed, checked the compass- the reading was about 1250.
    Selected calibrate, did the turn clockwise- it took 2 times around before the light changed green.
    I then did the turn with the nose pointed down. just as I finished the turn there was a very strong gust of wind that made one of the props start to rrotate (about 2-3 turns I think), this was at the same time the lights started flashing green. Then the motors started turning randomly. If I remember correctly only three of them actually started one never did. Also the gear went into the flight position. The controller was sitting on the ground about 5 meters away from me and there was no one else in view.
     
  8. Kirk Pleasant

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    I will try and download the log file to DJI... needless to say- it scared the hell out of me!
     
  9. Kirk Pleasant

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    It is now 0030 where I live and a busy day scheduled for tomorrow.
    Sorry to be lazy but if anyone has a link on how to download the log file it would be greatly appreciated.

    Cheers
     
  10. kiwia

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    This maybe a naive question, but since I updated the pilot app the "calibrate compass" button has disappeared? Am I missing something?
     
  11. Mani

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    Altough we share the same time , it's also 01.03 here where I live, I do hope we do not share the same luck, as you are the first Inspire owner to report an uncommanded motor start.
    Seriously, is this for real ?
    Sorry if I have to double check your honesty, but this kind of error makes all the flyaways reported so far completely insignificant.
    If it's true, I'll take the bad news as good as it gets, as it creates a new market opportunitty, I am thinking to design a compass calibration extender, like a selfie stick, to keep the possesed drone away from me ( yes, this error reminded me of The Exorcist movies )

    P.s also it seems that 3DR Solo needs to completely rethink their marketing campaign, the one with " autonomous flight, smartest drone ever" doesn't work anymore, as it doesn't have autostart, like your Inspire.
     
  12. Kirk Pleasant

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    Mani,
    It is absolutely real.
    I know The Editor says it can't happen but fly-ways, voltage drops and loss of controls are not supposed to happen but they do.
    I will send an email this morning to DJI and the flight logs once I figure out how to download them. I checked my Ipad flight records and there is nothing there. It didn't register it as a flight even though this lasted a few minutes.
    Maybe temperature was a factor. I had flown for 42 minutes (over 5 batteries, taking them down to about 60% so I could check them and then give them a full charge for a shoot today) with a temperature of about 38 - 40 deg C.

    Cheers
     
  13. The Editor

    The Editor Moderator
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    OK, so you had flown and then landed. Once your Inspire was on the ground you then cut the motors by holding the left stick down for a couple of seconds? The Inspire was still powered up at this point (but motors not spinning) and it was then you decided to check the compass mod value?
    You checked the mod value in the app and then chose to calibrate the compass (the Inspire had not been powered down from the proceeding flight at this point).
    You put the AC into calibrate mode presumably put the remote on the ground and started to do the compass dance? The first rotation took nearly two revolutions before a solid green light and after you did the nose down maneuver the motors fired up intermittently of their own accord. During the pulsing of the motors the landing gear moved into the flight position?

    Is there anything you can think off I have missed or is there anything that is in the wrong order etc?

    Finally, do you have self adaptive landing gear activated and do you use or did you use auto take off for the flight before this occurred?
     
    #13 The Editor, May 18, 2015
    Last edited: May 18, 2015
  14. Kilrah

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    Power up everything, go to advanced settings in the app, enter flight recorder mode, connect a computer to the USB port in the tail of the Inspire and grab the files there. There is one file each time you power up.
     
  15. Kirk Pleasant

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    That is all correct.
    The only slight variance is that I had just completed the nose down turn and the light started flashing green , within 1/2 second (thankfully I was still holding it out in front of me with the nose pointed down) is when the motors started pulsing.
    I don't know if temperature might have had something to do with it- it was about 38 deg and I had flown 42 min before the incident.
    I have just download the flight data. Interestingly I have 7 flight records for yesterday but 11 data logs.
    I will send DJI support a email and a wetransfer with the last 4 data logs. One is only 11MB in size. I am hoping that might contain the information that they need.

    Cheers
     
  16. Kirk Pleasant

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    Thanks,
    I figured it out.
    Cheers
     
  17. The Editor

    The Editor Moderator
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    Can you confirm my points re self adaptive landing gear and auto take off?

    I want to try and recreate the same sequence of events.

    Thanks
     
  18. Kirk Pleasant

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    Yes the adaptive gear was on but no auto takeoff.
    I had been flying varying between P, A and F modes
     
  19. Kirk Pleasant

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    I am happy to send you the data logs if that will help you.

    Cheers
     
  20. Kilrah

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    Only DJI have the tools to read the logs, which is why it's important to make a detailed issue report and talk to them.