Testing a DIYDrones magnetometer in HK's GCS

Testing a DIYDrones magnetometer in HK's GCS from Pete Hollands on Vimeo.

I test the DIY Drones magnetometer ( HMC5843 magnetometer breakout board ) using Happy Killmore's Ground Control Station connected using SERIAL_UDB_EXTRA telemetry format, to a UAV DevBoard V3 running
MatrixPilot (revision 729 of trunk).


UAVDevBoard / MatrixPilot:​p/​gentlenav/​wiki/​Home?tm=6

HK GCS:​p/​happykillmore-gcs/​

DIY Drones Store:​HMC5843_Triple_Axis_Magnetometer_p/​br-hmc5843-01.htm

Self Calibrating Mathematics, and software to integrate via I2c written by William Premerlani:-​profile/​WilliamPremerlani

Source Code:​p/​gentlenav/​source/​browse/​trunk/​libUDB/​magneto_udb.c

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  • Developer

    @HK MAVLink messages (common messages) should be identical for ArduPilotMega, PixHawk or MatrixPilot. Anyway, I'll go give it a try.

  • New GCS uploading now. I can't say for sure that I have the scaling right on the accel, gyros or mag.... But it does update with MAVlink only for right now. If anyone can tell me the variables I should look at in MatrixPilot I'd love to add it....

  • Developer

    Bryan, That's disappointing.

    Looks like that version of QGroundControl ( 0.76 ?) has a problem on Vista then.

    As it's Beta code, I'll check to see if anyone else is using Vista QGroundControl in their forum.

    You might like to run up HappyKillmore's GCS and test to see if that is working on the same link with the same setup of MatrixPilot Mavlink. If you get anything working (namely the 3D EasyStar), then that proves the problem is definitely in the QGroundControl and Vista and that your version of MatrixPilot is working correctly.

  • Pete,

    Data is arriving in the comm window and when I click on Hex I get the numbers.

    The coloured check boxes don't appear (the whole graph window doesn't appear) unless I click on simulated data and then click the simulated data box again.

    No numbers changing, no plotted data.

    Don't like Vista!

  • Developer

    Bryan, regarding testing the magnetometer using MAVLink and QGroudnControl:


    So data is arriving in the Comm Window ?

    You can click on Hex and see it arriving as Hexadecimal Numbers ?

    The Coloured Check Boxes are appearing (and by the way, they only appear when QGroundControl see's each of those variables arriving in the data stream). ?

    None of the Numbers next to any of variables (e.g. accel-x, or the gyros, or the roll, pitch and yaw) are changing ?

    I've been testing on Windows XP, and I think most of the developers of QGroundControl are probably on Linux / Mac. So it's possible we have a problem with QGroundControl under Vista (it is an early beta version of the code).


    If you could answer the questions above, then I think we could move to the QGroundControl discussion forum to follow this up.


    A new version of QGroundControl is due out.


    Best wishes, Pete


  • Hi Pete,

    Unfortunately the numbers are not changing next to the check boxes. Also, I've tried clicking on "ground clock".


    An option to display raw sensor data on your GCS sounds great. Looking forward to trying it out when it's ready.

    Thanks guys


  • The 3D model in the instruments is working with Yaw. The GE model is working with heading (there's a lag issue with Lat & Long values from several auto-pilots, so making the GE work with Yaw was very confusing to watch).. I'm also adding raw sensor readings to my GCS right now. I won't have a graph but it will show real time data values and a slider that represents the data. Hope to have that done this weekend.

  • Developer

    By the way, since I posted the HK GCS video, Happy has started to support MAVLink as well. So far, I know that his HK GCS will display the roll, yaw and pitch correctly for MAVLink. There is no additional setup to do on HKGCS, it will automatically start interpreting MAVLink if you send that to it. Note: I've only seen the "Easy Star" model working correctly with MAVLink so far.


    So again, another test is to fire up MatrixPilot Mavlink with HKGCS. Then, away from local magnetic disturbances, set the plane to be due North and South, so it's easy to see the orientation in the "Easy Star" instrument. Then fire up the motors, and see if the heading changes for the Easy Stgar.


    I hope QGroundControl works for you as well, so you can plot the raw magnetic sensor data. It been very interesting to see the raw data.

  • Developer



    Can you say whether the figures were changing next to the magnetometer values on the left hand side ? So I'm not talking here about the graph, but the numbers next to the "check box" for the 3 magnetometer vector values.


    If the numbers are changing next to the check boxes, then you are nearly there.


    To get the live plotting to work, you may need to click on "Ground Clock" under the graph.


    Best wishes, Pete

  • Well Pete,

    I downloaded qgroundcontrol and the Mavlink branch of Matrixpilot, set the options.h serial to Mavlink per your video tutorial, set the com port and baud rate and got serial coming into the GCS from Matrixpilot. The problem is I couldn't get the live plotting to work. My goal was to display the live magnetometer data on qgroundcontrol while moving the airframe around the magnetometer to check for magnetic deviation.

    I'm running Vista on my laptop and I've set the magnetometer option to "1". Is there something else I'm missing?



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