Hi,
My doubt is about the correct spec of CHR-6d Inertial Measurement Unit, in this link " pololu.com/file/0J342/chr6d_datasheet.pdf ", only two axes are mentioned (pitch (x), roll (y)),
What is correct?
I wish to use this IMU in my project but, I need the YAW axe. However, this IMU doesn’t have the YAW, can I change the sensor position, and use for example the “roll axe”, like yaw axe.
My project is a robot, and I need mensure the YAW angle. 
Thanks
BRuno
Hello.
The CHR-6d outputs acceleration data for all three axes (X, Y, and Z), and it has roll, pitch, and yaw gyros that give you angle rate of change information about the X, Y, and Z axes. It uses an EKF filter to estimate pitch and roll angles from this data, but because it lacks a magnetometer/compass, it can’t do a very good job of maintaining an accurate estimate of the yaw angle. You can use the yaw gyro to tell when you’re turning and approximately how much, but over time your notion of absolute yaw angle will become less accurate as errors build up.
If you want a sensor that tells you your absolute yaw angle, I suggest you take a look at the CHR-6dm AHRS.
- Ben
