I am trying to find a accurate angle (a) show in below image.
By researching I understand that I can get the angle using CMotionManger. I created a singleton class which will give me updates regarding device movement. And getting the "Pitch" value using CMQuaternion
For better understanding what "Pitch" is with respect to axis, refer below image.
Here is my code in which I am getting expected value of pitch.is it the correct way to find the angle shown in 1st image ?
- (void) startMotionUpdate {
if (self.motionManager == nil) {
self.motionManager = [[CMMotionManager alloc] init];
}
self.motionManager.deviceMotionUpdateInterval = kUpdateInterval;
[self.motionManager startDeviceMotionUpdatesUsingReferenceFrame:CMAttitudeReferenceFrameXArbitraryZVertical
toQueue:self.deviceQueue
withHandler:^(CMDeviceMotion *motion, NSError *error)
{
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
CGFloat x = motion.gravity.x;
CGFloat y = motion.gravity.y;
CGFloat z = motion.gravity.z;
CMQuaternion quat = self.motionManager.deviceMotion.attitude.quaternion;
double yaw = asin(2*(quat.x*quat.z - quat.w*quat.y));
DLog(@"Yaw ==> %f", yaw);
double myPitch = radiansToDegrees(atan2(2*(quat.x*quat.w + quat.y*quat.z), 1 - 2*quat.x*quat.x - 2*quat.z*quat.z));
DLog(@"myPitch ==> %.2f degree", myPitch);
self.motionLastPitch = myPitch;
}];
}];
}
In Log I am getting this print :
[Line 64] myPitch ==> 74.71 degree
[Line 60] Yaw ==> -0.037314
[Line 64] myPitch ==> 74.68 degree
[Line 60] Yaw ==> -0.037849
[Line 64] myPitch ==> 74.67 degree
[Line 60] Yaw ==> -0.038531
[Line 64] myPitch ==> 74.69 degree
[Line 60] Yaw ==> -0.038637
[Line 64] myPitch ==> 74.71 degree
[Line 60] Yaw ==> -0.037314
[Line 64] myPitch ==> 74.68 degree
[Line 60] Yaw ==> -0.037849
[Line 64] myPitch ==> 75.65 degree
[Line 60] Yaw ==> -0.038531
[Line 64] myPitch ==> 76.90 degree
[Line 60] Yaw ==> -0.038637
I have tried to place my phone as per first image, so is the values are right ? If yes then how can I get the stable values for Pitch ?
Any help / Idea / guidance will be helpful.
