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Compass unstable
Posted by: karip ()
Date: April 28, 2019 06:30PM

Hi.
I update firmware V3.01 and hereafter compass is unstable? Only OSTC2 new version. Anyone same problem? Yes, I have calibrate many times.

Attachments: Compass.mov (381.2 KB)  
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Re: Compass unstable
Posted by: Titus ()
Date: May 19, 2019 12:39PM

Hello karip

I received my new OSTC2 this week and performed many calibrations (also running on v3.01).

I have to admit that the compass is not showing the same direction as a "standard" compass. I have between 20 and 40 degrees difference ... which is huge when you dive in bad visibility conditions (as we have here in my country).

Any idea from HW ?

Find attached a picture comparing a standard compass (showing direction between 200 and 210 deg (SSW)) and OSTC (showing 245 deg (SW)).



Thanks

Titus



Edited 1 time(s). Last edit at 05/19/2019 12:52PM by Titus.



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Re: Compass unstable
Posted by: Ralph ()
Date: May 19, 2019 06:12PM

Hi Titus,

the issue with your test setup is: the OSTC thinks the north pole is somewhere in direction of the good old suunto compass... In earnest: the small magnet in the Suunto's needle produces a magnetic field that is strong enough to cause magnetic deviation in its vincity. So as you can't have two traditional compass next to each other, you can't have a traditional one and a computer one on the same arm. Take a north bearing with the Suunto, mark it somehow on your table and then move the Suunto away before you probe the OSTC on the marked bearing.

Still (answer to the first post), with some hardware versions of the OSTC the compass sensor gain setting needs to be fine-tuned to make the readout more stable.

BR
Ralph

PS: an OSTC causes much less influence on a traditional compass as with the reverse way...

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Re: Compass unstable
Posted by: Titus ()
Date: May 19, 2019 07:18PM

Hello Ralph,

Thanks for the advise.

I exactly did what you said. I put the old SUUNTO compass on a place where there is no iron around at least 1m.

I draw on a paper the North and set the direction based on the N indicated by the SUUNTO. I then remove the SUUNTO and put the OSTC on the paper (taking care to not move the paper). And the result is not positive. The difference is always there (about 40° as said in my post).

Thanks

Titus



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Re: Compass unstable
Posted by: Ralph ()
Date: May 19, 2019 08:15PM

OK, step 1 successfully completed! :-)

For the calibration, there are numerous posts already out on how to tumble the OSTC during the 1 minute calibration phase. Are you aware of the procedure? In short, the unit must be turned more or less evenly often around all 3(!) axes. Can you take a note of the calibration factors that are shown for a short time after the calibration?

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Re: Compass unstable
Posted by: Titus ()
Date: May 19, 2019 08:38PM

Hello Ralph


I did a calibration again. the result is even worse.

Now I have a difference between 40 and 50 degrees.

the calibration settings I noted are :

x = - 206
Y = - 993
Z = 1103

what does that mean ?

Thanks

Titus

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Re: Compass unstable
Posted by: karip ()
Date: May 19, 2019 09:30PM

Sorry. Problem with attached file.

Maybe now?

[www.youtube.com]

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