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Pixhawk Pre-arm check fails "Compass not healthy"

Posted by Andy Piper on February 4, 2015 at 6:43am

AC3.2 on a 3DR 2014 DIY Quad with Pixhwak.

I have occasionally seen these and usually unplugging and plugging in the battery fixes things. However, today it would not clear and I could not get off the ground. I had done a short test flight earlier without issues in a different location. The compass direction in the telemetry seemed steady, but was indicating a different direction each time I rebooted.

I have recently change the configuration from Spektrum satellite to OrangeRX R800X and added a Fatshark 25mW 5.8GHZ transmitter. Are either of these likely to interfere with the compass? Or is it hardware failure?

Thanks for any info.

andy

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Replies

  • Kaan Ozgen April 22, 2016 at 11:42am

    I'm having the same problem. Even moving the vehicle too much around confuses the compass easily. A reboot clears it away. Is there a way to reboot compass when pixhawk is on?

  • Andy Piper April 10, 2015 at 7:18am

    Just to update anyone who googles across this. My findings are:

    - Compass not healthy does not mean hardware failure, it just means the sensor is overloaded.

    - Calibrating outdoors away from all possible sources of interference makes a huge difference.

  • This reply was deleted.
    • Andy Piper April 10, 2015 at 7:16am

      Thanks for the suggestion. Obviously the number of satellites picked up by the GPS will have no bearing on the compass performance. I don't want to disarm the check as a bad compass has potentially disastrous consequences.

  • Andy Piper February 7, 2015 at 8:03am

    An update on this. I recalibrated the compass very carefully without issue (selected Pixhawk in APMPlanner2). Calibration found two compasses - internal and external I assume - and the IDs were as documented in https://github.com/diydrones/ardupilot/issues/1355 - i.e. both had ID's, compass 2 was NOT -1. Is this correct? The compass heading in APM is correct and responds quickly to movement. Applied power and same result "Compass not healthy". Tried again and got "Compasses inconsistent".

    So here's a weird thing. I apply power with the copter not moving (obviously). If I then rotate the copter a little so that the heading viewed in APMPlanner2 moves the error goes away! This sounds more like a software than hardware issue to me, but knowing zero about the firmware I of course could be completely wrong. If a compass is faulty, how can I tell which one. How can I tell whether the calibration is reasonable?

    Thanks for any info/ideas

    andy

  • Andy Piper February 4, 2015 at 1:39pm

    I'm using the 3DR uBlox compass/GPS kit as well.

This reply was deleted.

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