I'm using coreMotion
in my app to detect a motion of iOS device. I know how to get the different sensor's data from coreMotion
. I am getting roll, pitch, and yaw data as follows from the deviceMotion
:
float pitch = (180/M_PI)*self.manager.deviceMotion.attitude.pitch];
float roll = (180/M_PI)*self.manager.deviceMotion.attitude.roll];
float yaw = (180/M_PI)*self.manager.deviceMotion.attitude.yaw];
How can I use these data to detect a motion? What are the calculations that I need to do for this?
The attitude values need the device motion updates to be started as:
startDevicemotionUpdates
To monitor attitude values when device moves, use the attitude values to be displayed in labels:
[self.cmMotionManager startDeviceMotionUpdatesToQueue:[NSOperationQueue mainQueue] withHandler:^(CMDeviceMotion *devMotion, NSError *error) {
float pitch = (180/M_PI)*self.manager.devMotion.attitude.pitch];
float roll = (180/M_PI)*self.manager.devMotion.attitude.roll];
float yaw = (180/M_PI)*self.manager.devMotion.attitude.yaw];
self.rollLabel.text = [NSString stringWithFormat:@"%f", roll];
self.pitchLabel.text = [NSString stringWithFormat:@"%f",pitch];
self.yawLabel.text = [NSString stringWithFormat:@"%f",yaw];
}
Also it is better not to use roll, pitch and yaw(aka Euler Angles). Use Quaternion or Rotation matrices for better accuracy. Euler angles have the tendency to be in a situation called gimbal lock which results in unreliable data.
Please check this link for how to use quaternion, and convert that value to the roll, pitch and yaw values: SO link
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