topic How to use 9 Axis system to get Roll , Pitch, Yaw using FXOS8700CQ + FXAS21000 ? in Sensors

How to use 9 Axis system to get Roll , Pitch, Yaw using FXOS8700CQ + FXAS21000 ?

Amit_Kumar1 — Tue, 03 Feb 2026 21:49:03 GMT

Is there any document or tutorial to get error corrected Roll, Pitch and YAW (AHRS) using 3 axis accelerometer + 3 axis Magnetometer +3 axisGyro. I tried finding the quaternion using Madgwick algorithm for AHRS but it didn't worked. When I tried changing the orientation from 0-90 degree , the values showed 0-360 degrees multiple times. So I wanted to follow the standards and make it work. In this I wanted self calibration and using these sensor error correction also. Please Look into the matter.

Kind Regards

Amit Kumar

Re: How to use 9 Axis system to get Roll , Pitch, Yaw using FXOS8700CQ + FXAS21000 ?

Martin35804 — Wed, 27 Aug 2014 11:09:05 GMT

Take a look at the FRDM-FXS-9AXIS: Freescale Freedom Development Platform for 9-Axis Xtrinsic Sensor Solution.

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=FRDM-FXS-9AXIS&fpsp=1&tab=Design_Tools_Tab

In the Downloads tab there is a Xtrinsic Sensor Fusion Library for Kinetis MCUs Software Development Kit. This should give you some hints.

Re: How to use 9 Axis system to get Roll , Pitch, Yaw using FXOS8700CQ + FXAS21000 ?

Amit_Kumar1 — Wed, 27 Aug 2014 11:24:25 GMT

Hi Martin

Thanks for the link. I have been through this lib. It is too confusing. and meanwhile I am stuck with the Magnetometer not working FXOS8700CQ Magnetometer Not Working Properly! After fixing this issue I will again look into this lib.

Kind regards

Amit Kumar

Re: How to use 9 Axis system to get Roll , Pitch, Yaw using FXOS8700CQ + FXAS21000 ?

jimmiller — Fri, 29 Aug 2014 18:32:41 GMT

pitch, roll and yaw can be gotten by taking raw accelerometer data and applying:

The results will be + or - 90 degrees.

pit = atan(Y/ sqrt(X^2 + Z^2))

roll= atan(X/ sqrt(Y^2 + Z^2))

yaw=atan(Z/ sqrt(X^2 + Y^2)

Good luck!

Re: How to use 9 Axis system to get Roll , Pitch, Yaw using FXOS8700CQ + FXAS21000 ?

Amit_Kumar1 — Sat, 30 Aug 2014 03:24:36 GMT

Hi Jim

Thanks for responding. I wanted complete AHRS. I agree that I will get Pitch, Roll, Yaw with the above equation but it the system is in accelerating frame that it will buildup some errors so to rectify that Gyro is needed and to rectify the gyro's error acc and magnetometer is needed so in short as a feedback i would be needing 9 axis for taking out AHRS.

Kind Regards

Amit Kumar

Re: How to use 9 Axis system to get Roll , Pitch, Yaw using FXOS8700CQ + FXAS21000 ?

michaelestanley — Thu, 04 Sep 2014 18:10:42 GMT

Try http://www.freescale.com/sensorfusion.