APM Orientation for Traditional Heli

I built a TRex 450 with an APM mounted as suggested by Randy but am thinking about changing it and mounting it in a different way that would result in the APM being upside down.  My question is, can I easily correct this by modifying the code?  Is it just a matter of changing the sign for a number of the signals?  I noticed there is a config parameter for changing the orientation of the magnetometer, but I didn't see anything for the orientation of the APM.





You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


  • Yes, great stuff!  Just made this mod to mount an apm1 under my 3DR frame.  Works tremendously. :)  The filename has changed but grepping on GYROY etc will turn it up.

  • Developer


         There's no easy way to do this I'm afraid.  It's definitely possible though but you'd need to modify perhaps the AP_IMU_Oilpan.h file in the AP_IMU library or maybe somewhere in the DCM lib when it consumes the accelerometer and gyro data..but I can't tell you exactly what you'd need to change.  If the APM is upside-down I think you need to reverse the pitch gyro values and all three (x,y,z) accelerometer values.

This reply was deleted.