PixRacer with Ardupilot

This is a discussion to focus the feedback and support of ardupilot on the PixRacer board from

We believe that all teething problems encountered are now resolved and so we recommend people load Copter-3.3.4 which is available for all multicopters through the Mission Planner's (and other GCS's) Install Firmware screens.  Note that because regular Pixhawks are still on Copter-3.3.3 the install icon may show Copter-3.3.3 but rest assured, Copter-3.3.4 will be installed (you can check the version by looking at the very top of the Mission Planner).


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              • Developer

                Are you using the "Live Calibration" button or the "Onboard Mag Calibration Start" button?

                The difference between these two is the "Live Calibration" is all done within the mission planner while the "Onboard Mag Calibration" is done on the flight controller (using software in ArduPilot).  The "Onboard Mag Calibration" should produce slightly better results.

                • T3

                  On 3.4dev with Onboard calibration it seems the offsets flip between X and Y:

                  Onboard: X: 357, Y: -144 Z: 9

                  Live:         X: -41, Y:  331 Z: 5

                  With onboard I get "Check magnetic field"

                  With live I get: "Compass not calibrated" 

                  Onboard is only calibrating two compasses.

                  • I used the live calibration as well (since I didn´t know what the onboard does) Auto Accept always finished far too early (after 180°),turned it off but still had a lot of calibration failures till I got it finished.

                    3702951316?profile=originalIt always showed Err 99 for the 3rd MAG, but spit out all offsets for it. Nevertheless, I didn´t notice any abnormal behavior during flight.(AltHold/PosHold/Land) Except, that it seemed, that GLONASS was gone despite of Bitmask 67, PosHold behaved a lot worse than it did with the PX4 stack I tried right afterwards (to check if sth. is wrong with the GNSS)

                    3702951358?profile=originalConsistency looked fine for me.

                  • T3

                    PS: the live calibration values differ from the screenshots above to some degree due to some rearranged parts

                • T3

                  I was using the "Live Calibration".

                  I'll give the Onboard version a try. 

                  On 3.3.4 I now had "Inconsistent Compasses"


            • Developer

              Re just the last point, I suspect that the vehicle was either in a mode that requires GPS (i.e. Loiter, PosHold, etc) or the circular fence was enabled.  The circular fence requires a 3D lock because other wise it doesn't know where it is (so it can't enforce the fence).

              • T3

                Ahh, ok! Fence is on...

                Makes sense!


        • Michael, adding a little to it, even in stabilize mode I feel like the quad is constantly starting to move in a direction on its own, then I pull it back, fine for a few seconds, before it moves away on its own again usually in another direction.

          Are you also seeing that.

          • Developer


            I've only had a quick look at your log but your compass #2 looks to be very bad.  The mag field for compass #2 seems very bad which also indicates a bad compass calibration (or something like that).  The field length is insanely high (>1400) at the beginning but drops massively to 600 when the vehicle flips over.  Mag3's field length is also far too large.

            3702861134?profile=originalDefinitely something going wrong with the compass calibrations.

            Things like this which is why we recommend not flying master.  There's just many things we haven't fully tested yet.  Not that it makes anyone here happy because realistically flying Copter-3.3.3 with pixracer is not a great experience yet.

            • First thanks, and yeah, I can not get any good reading at all from compass 2.

              I do have it unchecked in MP and have only flown stab mode for now but it almost acts as if compass 2 is still trying to move the coper or something. Thanks for the feedback and all the great work.

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