Landing on the bridge. Compass error. Atti mode.

[Gabriel Nan]

Hey. Help solve my problem. Yesterday, my drone landed because of a discharged battery - the drone landed on a road bridge. Miracle - I managed to pick him up from the road. After that, I always had a compass error and the drone itself goes into atti mode. What happened? How to repair it?

 

[nilanjan118]

Have you tried calibrating the compass? Here is a thread similar to your problem. Please take a look.

Compass error after storage in a cold car.

Hey. Accidentally forgot the drone in the trunk of the car. He lay there for 2 days (the temperature outside was -5 degrees). Today I launched a drone - immediately after takeoff, a compass error appears and the drone goes into atti mode. What happened? How to fix it?

sparkpilots.com

 

[Paul215]

The drone compass don't like ferrous metals like iron. Have you tried a new calibration?

 

[ExcitingHeadgear]

Here is a video on how to calibrate. Do it somewhere away from any metal:

 

[McCloudSpark]

I don't understand - why is there still a compass error after leaving the bridge? The negative effect of the metal bridge should be gone - right? Are you saying that landing on the bridge permanently changed the compass calibration?

 

[nilanjan118]

I don't understand - why is there still a compass error after leaving the bridge? The negative effect of the metal bridge should be gone - right? Are you saying that landing on the bridge permanently changed the compass calibration?

Take a magnet. Pick up a nail with it. While it is still attached to the magnet, take the nail near some small pins. The pins will get attached to the nail. Now remove the magnet. You will find that the pins start to fall off but some pins still remain attached to the nail.
Hope this explains why the compass error is still there.

 

[lmel2005]

It is strange, because seems that the bridge, magnetised some parts of the spark.
And this, doesn't happen often.

 

[McCloudSpark]

Take a magnet. Pick up a nail with it. While it is still attached to the magnet, take the nail near some small pins. The pins will get attached to the nail. Now remove the magnet. You will find that the pins start to fall off but some pins still remain attached to the nail.
Hope this explains why the compass error is still there.

So, the compass in the Spark has a magnet in it and the bridge has affected this magnet enough to cause a calibration error. Maybe?

 

[Andre Levite]

So, the compass in the Spark has a magnet in it and the bridge has affected this magnet enough to cause a calibration error. Maybe?

Here's a clearer analogy that explains the bridge related compass error...

Let's say you step on a scale with a duck. But when you step off the duck remains and the scale fails to return to zero. Now you need to recalibrate your scale. That's how the Spark compass works. It has a duck inside it. Not magnets -- that would be silly.

 

[Spark 317]

That's how the Spark compass works. It has a duck inside it.

Well heck, that explains why my Spark drifts to the south in the Autumn and drifts north in the Spring.

I need to recalibrate my duck. ?

 

[nilanjan118]

So, the compass in the Spark has a magnet in it and the bridge has affected this magnet enough to cause a calibration error. Maybe?

In simple terms, yes. A compass is nothing but a small magnet which aligns itself with the magnetic north of the earth to tell us the direction. If you see the thread I shared in post #2, you will find a similar case where someone stored his Spark in his car trunk and the prolonged exposure to the metal all around upset the compass. But as you rightly said, the compass error we normally see when the Spark is near a metal object usually goes away when we move away from the metal. May be when the metal is big enough and the exposure is long enough, the error stays.

 

[McCloudSpark]

So Gabriel - did the compass re-calibrate solve your issues?

 

[lmel2005]

There's not a magnet in an electronic magnetometer.

 

[nilanjan118]

There's not a magnet in an electronic magnetometer.

Read a long time back in high school - There is an intrinsic relationship between electricity and magnetism.
Pass electricity through a coil of wire and you get a magnet; oscillate a magnet near a coil of wire and you get electricity.
Ok, enough of high school physics.
Did the OP get his issue resolved?

 

[lmel2005]

Read a long time back in high school - There is an intrinsic relationship between electricity and magnetism.
Pass electricity through a coil of wire and you get a magnet; oscillate a magnet near a coil of wire and you get electricity.
Ok, enough of high school physics.
Did the OP get his issue resolved?

Yes I know, but a coil is a coil, a magnet is a magnet, and a coil cannot be magnetised permanently.

If a compass calibration cannot solve OP's problem, he should try a demagnetiser, as CFIXER.

 

[twickers14]

Just a thought reading this. I can’t remember exactly what warnings I got (think they might have been about the compass) but I had a habit of placing my Spark on the top of my car roof while I popped the RC etc onto the back seat. I know, I should invest in a proper bag and may pick one up in Naples FL in May. I do not do that any more and I haven’t had any repeat warnings. Could be coincidence but just in case, hope this helps.

 

[Gabriel Nan]

Thank you all for the answers. I read many articles on the forum. I realized that my compass is magnetized. I demagnetized the compass with a special device (cfixer) - the error disappeared.?

 

[McCloudSpark]

Thank you all for the answers. I read many articles on the forum. I realized that my compass is magnetized. I demagnetized the compass with a special device (cfixer) - the error disappeared.?

Gosh - cfixer sure is expensive! So glad that it worked for you!