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

            Can you check the pinout of the canbus cable. Some cables may have been sent out with wrong pin ordering.

            Next, start a nsh over MAVLink shell and run the command "uavcan status" and show us the result.


            • Andrew, here is the result

              UAVCAN status
              UAVCAN: application not running
            • The cable checks out OK. I can't get the terminal to work in APM Planner so will have to wait until tomorrow until I can get on a Windows machine with MP. I will let you know, thanks again
  • Developer

    Small update from Paul Riseborough regarding the sudden-roll-after-takeoff issue.  It seems a bug in the EKF is somewhat likely and it probably only happen if you take-off without GPS lock and then gain GPS lock soon after.

    So if you want to avoid the problem, waiting until you have GPS lock before take-off is a good idea.  Note that I say, "wait for GPS lock" but to be more precise, it's actually "wait for the EKF to get a position estimate".  You can ensure this is the case by arming in a mode that require the EKF's position estimate like Loiter or PosHold.

    • Nice to know it wasn't me causing the issue.  I thought maybe I was on drugs or something.

      So if you fly without a GPS it should work just fine as well...

      On another note it seem the Pixracer has LED's on the mother board not connected to the I2C bus.  They need to be turned on directly.  Since the code makes no distinction of that only the external LED's work.  On the PX4 stack they use an RGBled driver to control them.  Is this on the list to get working.  It would be nice to see if I have a GPS lock.....

  • I have never been able to calibrate the accelorometer in MP but have no problems calibrating it using QGC. I level it up and get started but after pressing any key after level it just stops sometimes it says ublox and some numbers and others it says left side and before I can rotate it I get an error. Good thing is I can use QGC and calibrate it and get it to arm in MP. Also , thanks Tridge, the oneshot 125 is working. Motors are now as smooth as silk now.

    • I have the same problem. Pixracer accelorometer cannot be calibrated in MP but even in QGC it is not possible. Need some idea how to fix it.
  • The only thing I am missing is a osd, does the pixracer support a small osd and if so what one.

  • Developer

    I've pushed another update for brave testers to try. It will be in the autobuild in a couple of hours.

    The new update makes the following changes:

    • fixes OneShot125 on BLHeli ESCs to not need power on board before ESCs
    • fixes so that only fast ESCs get oneshot and high rate. This prevents trying to run a tricopter tail servo at 400Hz
    • fixes use of safety switch to prevent any pulses before the safety is disabled

    I would appreciate some test reports!

    If you have previously tried MOT_PWM_TYPE=2 and it didn't work then please try it again with this change.

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David Hori liked Isabella Domi's profile
Jan 12