Detecting Shake Gesture by CoreMotion

Question

I want to detect device shake using coreMotion framework for iOS 7. Can anyone help me out how to do this ?

I wrote code described below in my viewDidAppear

CMMotionManager *motionManager = [[CMMotionManager alloc] init];
    motionManager.deviceMotionUpdateInterval = 1.0/60.0;

__block double myAcceleration;
[motionManager startDeviceMotionUpdatesToQueue:[NSOperationQueue mainQueue]
                                   withHandler:^(CMDeviceMotion *motion, NSError *error)
 {
     myAcceleration = motion.userAcceleration.y;
     CATransform3D transform;
     transform = CATransform3DMakeRotation(
                                           motion.attitude.pitch, 1, 0, 0);
     transform = CATransform3DRotate(transform,
                                     motion.attitude.roll, 0, 1, 0);
     transform = CATransform3DRotate(transform,
                                     motion.attitude.yaw, 0, 0, 1);
 }
 ]; 

but not detecting shake.

Answer 1

  #define accelerationThreshold  0.30

- (void)motionMethod:(CMDeviceMotion *)deviceMotion

{ 

 CMMotionManager *motionManager = [[CMMotionManager alloc] init];

    CMAcceleration userAcceleration = deviceMotion.userAcceleration;
    if (fabs(userAcceleration.x) > accelerationThreshold || fabs(userAcceleration.y) > accelerationThreshold || fabs(userAcceleration.z) > accelerationThreshold)
    {
        float sensitivity = 1;
        float x1 = 0, x2 = 0, y1 = 0, y2 = 0, z1 = 0, z2 = 0;

        double totalAccelerationInXY = sqrt(userAcceleration.x * userAcceleration.x +
                                            userAcceleration.y * userAcceleration.y);

        if (0.85 < totalAccelerationInXY < 3.45) {
            x1 = userAcceleration.x;
            y1 = userAcceleration.y;
            z1 = userAcceleration.z;

            float change = fabs(x1-x2+y1-y2+z1-z2);
            if (sensitivity < change) {

              // print change in position in coordinates.
                NSLog (@"total=%f x=%f y=%f z=%f timeStamp:%f, UpTime:%f", totalAccelerationInXY, userAcceleration.x, userAcceleration.y, userAcceleration.z, deviceMotion.timestamp, [[NSProcessInfo processInfo] systemUptime]);

                x2 = x1;
                y2 = y1;
                z2 = z1;
            }
        }
    }
}