OSTC 5 Compass not working and has never worked

OSTC running hwOS4 Firmware
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Divert
Posts: 35
Joined: 24 May 2024, 00:06

OSTC 5 Compass not working and has never worked

Post by Divert »

The compass of my OSTC 5 is still not working and has never worked, I thought a firmware update would take care of this but no. I can't seem to calibrate it, and therefore the reading is wrong and inconsistent to pitch angle.

Here is the video of me trying to calibrate which does not pass from half the pitch portion. And the inconsistent result of the compass after the calibration process.

https://youtu.be/7iBTmYR54ho

Please advice.

Humberto.
heinrichsweikamp
Posts: 4484
Joined: 13 May 2007, 18:07

Re: OSTC 5 Compass not working and has never worked

Post by heinrichsweikamp »

In your Video you're rotating every other axis then the pitch axis. That will not work like this. The manual describes this in more detail and we have a video for the old OSTC sport (Which we emailed you already) and will make a video for the OSTC 5 sometime in the future.

Regards,
Matthias
Divert
Posts: 35
Joined: 24 May 2024, 00:06

Re: OSTC 5 Compass not working and has never worked

Post by Divert »

Thank you, I guess I don't have. A clear understanding of which is the pitch axis, I will check the video and keep trying.
heinrichsweikamp
Posts: 4484
Joined: 13 May 2007, 18:07

Re: OSTC 5 Compass not working and has never worked

Post by heinrichsweikamp »

Hi,

How to calibrate the OSTC 4 or 5 in less then 15 seconds:

Hold the OSTC in both hands and look to north more or less (Makes the calibration quicker)

Pitch axis: Rotate the OSTC slowly while the screen is always facing to the right
Roll axis: Rotate the OSTC slowly while the buttons are always facing to the right
Yaw axis: Rotate the OSTC slowly with the screen always facing up

You'll see all graphics will turn green quickly.

Regards,
Matthias
UrsiGill
Posts: 1
Joined: 11 Oct 2025, 08:16

Re: OSTC 5 Compass not working and has never worked

Post by UrsiGill »

Ugh, compass calibration is always the worst part of a new dive computer setup. 😖
Matthias is spot-on—it totally looks like you're trying to roll it instead of pitching it during that part of the sequence.
The easiest way to visualize the pitch rotation is to hold the OSTC flat like you're reading it on the surface, and then slowly tilt it forward and backward (like nodding your head) so the screen faces the sky, then the horizon, then the seabed.
It's super counter-intuitive, but once you get that motion right, it usually flies through the rest of the calibration!
You can also try this tool for free. https://123compass.org/
Divert
Posts: 35
Joined: 24 May 2024, 00:06

Re: OSTC 5 Compass not working and has never worked

Post by Divert »

I does not work no matter what I do. I have tried so many times. There's only 3 possible axes of rotation I have tried every one of them with no luck.

Here is yet another video of my trying what @heinrichsweikamp (matthias) suggested and also what @UrsiGill suggests. Nothing works.

https://youtu.be/SZM0XC9ZAKs

Matthias could this be related to the ostc4 battery inserted into the ostc5 ?

Is this hardware issue, software? I am running #1517 V1.7.3 firmware.

Humberto
Thorsten
Posts: 27
Joined: 15 Jun 2008, 10:03

Re: OSTC 5 Compass not working and has never worked

Post by Thorsten »

Hi Humberto,

I had a look at the video and it looks like you missed one direction while turning the OSTC (only half turn) you see that the pitch is 50%.
You can do it by try and error => start turning the OSTC and check if the bars are changing to green. If they do it is the correct axis. If not try another one.

Thorsten
Divert
Posts: 35
Joined: 24 May 2024, 00:06

Re: OSTC 5 Compass not working and has never worked

Post by Divert »

Thorsten wrote: 07 Nov 2025, 08:09 Hi Humberto,

I had a look at the video and it looks like you missed one direction while turning the OSTC (only half turn) you see that the pitch is 50%.
You can do it by try and error => start turning the OSTC and check if the bars are changing to green. If they do it is the correct axis. If not try another one.

Thorsten
I have done this litteraly a hundred different times! every possible way, even spend the whole time in each one of the only 3 possible axis, nothing works, it never gets past 50%. I can tell you. It is not me doing it wrong. I can assure you. What else can it be? Hardware? Software?

Please help me, I want to use my OSTC5 But without a compass it is not very useful.

Humberto.
swissdiving
Posts: 844
Joined: 30 Jul 2011, 07:30

Re: OSTC 5 Compass not working and has never worked

Post by swissdiving »

email HW to have the unit looked at...
Cheers,

Hansjoerg

--> 2N - 2201 / 3892
--> OSTC4 - 257 / 392 / 424 / 1324 S8
--> OSTC5 - 1507 S8

RTFM
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