a sensor that can measure position in xz plane (the plane an acccelerometer cannot measure)

[tedhuntington]

Is there a sensor that can measure position in xz plane (the plane an accelerometer can't measure)- I thought about perhaps an emitter that you know is at 0 degrees, or that you know is in the center, and a sensor that then measures it's position in the XZ plane relative to the emitter signal

[bryce · Accepted solution]

Hi Ted.  If you are trying to measure yaw angle for which the gravity detection of an accelerometer does not work then we have a potential option that is already proven.  If you take advantage of the earth's magnetic field and use Freescale's sensor fusion.  freescale.com/sensorfusion .  This would give you an ability to use the eCompass function to get the angle you need.  As the sensor fusion is open source, it would be possible for you to take what is there and adjust for your specific need.

Without knowing more about your use case, it sounds like this would be a good option.  Let me know what you think and if there are constraints why this type of system would not be effective.

[tedhuntington]

Wow do I feel stupid, that is so simple an answer: an electronic compass, of course! I see that there not only ecompasses (magnetometers) but apparently there are now even devices that integrate both an accelerometer and magnetometer to give the full 3D vector of the device.

Thanks a ton!

Ted