Compass nightmares

supermachoalpha · Feb 19, 2019

I find it interesting that when I first got my Air, I had to compass calibrate nearly every other flight. 2 days in a row now I have ran through 3 batteries and not a single time did I have to calibrate anymore. Makes me like my Mavic Air more lol.

Hungrypilot · Feb 19, 2019

Hi Garry:

Very interesting story, mostly because I recently posted about the same issues.

I was recently in Chile (Santiago and Vina del Mar) and I was unable to fly the entire time, both in and outside of cities. Either there is some weird bug, or there's some serious ferrous material in the ground. I got constant compass errors unless I was in my highrise hotel away from the ground...

I haven't contacted DJI yet, but it was interesting to hear the same issues with someone else. I was very sad to not be able to fly a single time down there

Cheers,
Joshua

GalDizzle · Feb 23, 2019

sar104 said:
Post a DAT file. That will show all the compass calibration data, calibration parameters, and the reason for the calibration requests.

Mobile device DAT file: How to retrieve a V3.DAT from the tablet

DAT file attached. what program can I open this in to review? useful knowledge for the future.

It appears rather bizarre still. I walked 100m from the site of switching the drone on to fly.

Also noted (albeit I haven't fully testedthis out yet) that when the drone was facing north or east it appeared to get the message in the air.

GalDizzle · Feb 23, 2019

Hungrypilot said:
Hi Garry:

Very interesting story, mostly because I recently posted about the same issues.

I was recently in Chile (Santiago and Vina del Mar) and I was unable to fly the entire time, both in and outside of cities. Either there is some weird bug, or there's some serious ferrous material in the ground. I got constant compass errors unless I was in my highrise hotel away from the ground...

I haven't contacted DJI yet, but it was interesting to hear the same issues with someone else. I was very sad to not be able to fly a single time down there

Cheers,
Joshua

Just getting back online again and read this.

Its a consistent issue and ongoing in Argentina. If I switch the drone on and launch the app (and have satellite reception) the app shows a home point. If I simply walk 100m away (so the app shows im at a distance of 100m) the message disappears. Utterly bizarre.

I fully believe I have a defective unit around the compass now, there is a DJI store in B Airies I will be visiting to see if they can help.

Hope you've been able to get it back in the air now!

GalDizzle · Feb 23, 2019

mustmoto said:
I had the same issue for the last 2 weeks. I tried calibrating over and over with no luck. Out in the middle of nowhere, in park, or my backyard-it didn't matter.

When looking at the compass sensor reading interference was in the green in the 30s. Still no go.

Finally figured somehow my compass or the the hardware around my compass was magnetized. Went to home depot and bought a tool demagnetizer for $2.97.

Rubbed it all around the compass while the drone was off and tried to calibrate... still no good. Hmm.. dang it.

Left the mavic air on and placed the demagnetizer on the tail above the compass. Looked at the compass sensor and it spiked to 999. Removed the demagnetizer and it dropped back down to 31. I then tried calibrating and BINGO!!!

Ran 5 batteries in 3 locations separated by 20 miles today. Didn't have a single issue.

This is the demagnetizer I used.

Interesting! If I cannot get it sorted in the DJI store this will be the next step I feel. It has been through a lot of plane journeys and xray machines etc so I am definitely leaning towards there being a hardware defect of some sort. The fact the message disappears if I set a home point and walk 100m away is the most bizarre thing although it does allow me to fly it if I have satellite reception and the app can track I have walked that 100m! No good if there are no satellite modes though (ATTI mode) as that can track the 100m.

I've read a lot of threads on this kind of issue and the mavic air definitely has a weakness in there somewhere which needs identified and corrected (or at least a solution listed)

Thanks
Garry

mustmoto · Feb 23, 2019

I'm telling ya. A demagnetizer fix all my issues. Haven't had a problem yet..

GalDizzle · Feb 23, 2019

mustmoto said:
I'm telling ya. A demagnetizer fix all my issues. Haven't had a problem yet..

ill learn how to ask for one in Spanish asap and hope it works!

sar104 · Feb 24, 2019

GalDizzle said:
DAT file attached. what program can I open this in to review? useful knowledge for the future.

It appears rather bizarre still. I walked 100m from the site of switching the drone on to fly.

Also noted (albeit I haven't fully testedthis out yet) that when the drone was facing north or east it appeared to get the message in the air.

That's a txt log, not a DAT file. You need to follow the instructions in post #11.

GalDizzle · Feb 24, 2019

sar104 said:
That's a txt log, not a DAT file. You need to follow the instructions in post #11.

so it is! correct corresponding .DAT file attached.

Mrmund · Feb 24, 2019

mustmoto said:
I'm telling ya. A demagnetizer fix all my issues. Haven't had a problem yet..

Which one?
Can you precisely describe your method?
Tnx

sar104 · Feb 27, 2019

GalDizzle said:
so it is! correct corresponding .DAT file attached.

I'm not sure what else might be happening, but the magnetometer data are extremely noisy - far more noise than is normal for these sensors. That looks like some kind of hardware issue to me.

mustmoto · Feb 27, 2019

Mrmund said:
Which one?
Can you precisely describe your method?
Tnx

End of page one on this thread explains what and how.

GalDizzle · Mar 7, 2019

sar104 said:
I'm not sure what else might be happening, but the magnetometer data are extremely noisy - far more noise than is normal for these sensors. That looks like some kind of hardware issue to me.

View attachment 64339

Ok - thanks. Out of curiosity how would the graph look if everything was good? Less spiking I assume?