Posted on June 23, 2012 at 19:38...and the calculated degree is also correct. ...
...the degree is keep increasing very fast, why?
Please keep in mind that a gyro does
NOT give you information about the current position or angle, but about the
rate of change of angle.
Gyros in this price range are not useful for deriving static information, their zero point noise and drift are to large for that. I don't know your code, but that would be a kind of unhopeful endeavor.
I suggest to use the accelerometer data instead for this purpose. As you learn early in physics - if an object stands still, or moves with constant velocity, only gravity is acting on it. That means, you should measure the equivalent of 1g as vector sum on all axes, depending on the alignment of the device to gravity. If the object moves, the acceleration forces add to gravity, but this is algorithmically manageable, and no really a performance challenge for a Cortex M3.
If your sensor data are correct, you are a great step further. The rest is applied physics. If you would like to do some research, look like robots or model airplanes and heliocopters navigate, using acc/gyro data.
