Thanks for the description of your calibration method, interesting stuff indeed. I purchased components to make my 3 gimbal calibration device already. I am using 1/2 CPVC with 90deg elbows. Actually ended up being really cheap, about $14 for everything. I think I am going to write my own calibration program, even if I can get my sensors calibrated with the FreeIMU calibration tool, just so I can gain a better understanding of these sensors. And because, I find the FreeIMU calibration tool cumbersome to use.