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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Yes, that should work.  So you could use the two remaining pwm outputs to control a gimbal for example.

Because the 6 outputs on the pixracer are actually the same as the six "AUX OUT" pins on the regular Pixhawk those last 2 pins might be Relays by default.  If that's the case then we might need to set the BRD_PWM_COUNT to 6 (instead of it's default 4).

We should also double check the output rate of the pwm (it's 400hz for motors but normally 50hz for servos) but again I'm pretty sure it should work because Tridge (who did the port of ardupilot to the pixracer) talked of using it to control a helicopter which requires 5 or 6 outputs.


It should be possible to make the 2 remaining pins either relays or pwm outputs by changing the BRD_PWM_COUNT parameter to be 6 (for all pwm outputs) or 4 (4 pwm outputs and 2 relay output).

We haven't tested it but i should work and if it doesn't we will fix it I think.

I thought the relay pins were set to the AUX pins and not the RCout pins.  The PWM count seems to indicate the number of AUX pins not PWM.

Ok, so yes, on the regular Pixhawk, the BRD_PWM_COUNT allows changing the AUX pins to be either Relays or PWM outputs but on the pixracer it allows the main RCOutputs to be changed.  The underlying reason this is possible is that in fact, the pixracer's 6 outputs are wired like the original pixhawk's aux outputs in that they're driven directly from the main cpu instead of going through the I/O board.

Roughly speaking the pixracer is a pixhawk with the I/O board removed.  It's the pixhawk's "MAIN OUT" pins that have been chopped leaving only the "AUX OUT" pins.

Dang Randy thats totally awesome.  I did another Racer sub 250g project using an APM mini, I had no idea this mini pix existed or I would have used that.

Yes, saw your discussion a moment ago.  Looking good!  The pixracer is very new and maybe the above quad won't be the last small quad you build? :-).

Great work!

For GPs have you tested the uBlox unit which you have put on your website( Is it the recomended GPS?

Found out, that the Rx bug is related to Radio Failsafe.(only FS I´m using) Independend of FS PWM level, its initializing FS,claiming no RC Receiver /RC FS, once activated.

The sts appearing Gyro/ Compass whatever health issues, partly with funny HUD level movements, Yaw movements are going away after re-boot.

Btw.,although this didn´t appear with PX4 stack, I changed my Hott Rx (GR-16, very reliable) to check, if this is hardware related. But that didn´t help.I flashed twice as well.

Due to variously other things going on, we didn't make a lot of progress today on sorting out the gyro health issue but we're pretty confident we know where it's coming from.  The low level IMU (accel/gyro) driver is kicking up errors probably because some register values we write are not staying at the value we wrote to them.  We just need to understand what's going on and put a work around in there.

Thanks Randy, like always.

The PixRacer looks like its a 30.5 mm stack like the CC3D, if so I can just remove the APM and stack the Pix on top of my PDB when this is ready for everyone to use.

I am very excited about this form factor, as you know I have been pushing for a smaller Pix for several of my builds.

Due to recent feedback, I have pulled this GPS from my site pending a through review. I have used them personally to good success, but I do not want to sell junk.

Thank you!

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