Pixhawk: can't calibrate external 3dr compass

Hi, I have problems to calibrate the external 3dr compass with my pixhawk.

Using Mission planner l select Pixhawk/PX4 and try live calibration.

I see for compass 1 and 2 error 99 and never more then 3 samples are collected.

The behavior is very similar to this one


A little bit more story.

First I bought a pixhawk together with an external 3dr GPS/Compass.

With this compass I could calibrate with no problem and GPS was also working.

But the compass seems to have an issue. When the pixhawk was running a while (e.g. > 10 minutes) the heading began to turn around faster and faster over time.

I calibrated the compass many times but this behavior always came back.

So I send it back and got a replacement.

Here I want to notice that the shipped 6 pin cable for this new GPS/compass for gps was a 6 to 5 pin cable.

I was a  little bit wondering and used instead a 6 to 6 pin cable.

With this new module live calibration isn't working.

I couldn't believe that this new module is not working and bough an additional module (which was shipped also with 6 to 5 pin cable).

Unfortunately this 3rd module is now also not able to be calibrated.

So what going on here???

I tried many things including flashing new firmware to the pixhawk, replace the I2C cable, replace the GPS cable but with no success. (calibrating the pixhawk internal compass works).

I also checked the pixhawk I2C supplied power and measure there around 4,7 V. Is that normal?

Could it have to do with a bad batch of these 3dr modules?

I bought them in Germany and because my both last modules were shipped with this wrong 6 to 5 this could be the case? Or it's me causing the problem? :)

Any hint what I can try to get it to work?

I'm really disappointed!



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  • Maybe the compass came in contact with a magnet and got degaussed somehow. There is a trick to repair this, but i only seen it with the DJI compass modules, although in escense they are very alike.

    You can check the video for reference...

    • Thanks for your reply Andreas but I don't think that this applies to both of the new compass modules. And I assume that the store isn't so stupid to place mangetic things near by the modules. :-)

      • well maybe by accident it did. And, by any chance, did you put it near  strong magnetic field.

        • I'm sure that this didn't happened from my side but I will take your hint into consideration if no one other has another idea what could be wrong.

          • Basiclly if all the circuitry is ok, then its just that the sensor is out of his standar operating parameter.

            Try sending it back to your provider as well, if it is just nwe, well just say that it came faulty

This reply was deleted.


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Apr 1