iOS Motion Detection: Motion Detection Sensitivity Levels

Question

I have a simple question. I'm trying to detect when a user shakes the iPhone. I have the standard code in place to detect the motion and this works no problem. However, in testing this on my actual phone, I've realized that you have to shake the device quite hard to get the motion detection to trigger. I would like to know if there is a way to implement a level of sensitivity checking. For example, a way to detect if a user lightly shakes the device or somewhere between light and hard shake. This will be targeted towards iOS 7 so any tips or advice that is not deprecated from older iOS version would be greatly appreciated. I've done my googling but have yet to find any good solutions to this problem (If there are any.)

Thanks!

-(void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
    if(motion == UIEventSubtypeMotionShake)
    {
       //Detected motion, do something about it 
       //at this point.
    }
}

-(BOOL)canBecomeFirstResponder
{
    return YES;
}

-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    [self becomeFirstResponder];
}

-(void)viewWillDisappear:(BOOL)animated
{
    [self resignFirstResponder];
    [super viewWillDisappear:animated];
}

Answer 1

Heres how I did this using Swift 3.

Import CoreMotion and create an instance

import CoreMotion
let motionManager = CMMotionManager()

On ViewDidLoad or wherever you want to start checking for updates:

 motionManager.startDeviceMotionUpdates(to: OperationQueue.current!, withHandler:{
            deviceManager, error in
            if(error == nil){
                if let mgr = deviceManager{
                    self.handleMotion(rate: mgr.rotationRate)
                }
            }
        })

This function takes the rotation rate and gets a sum for the absolute values for x,y and z movements

  func handleMotion(rate: CMRotationRate){
        let totalRotation = abs(rate.x) + abs(rate.y) + abs(rate.z)

        if(totalRotation > 20) {//Play around with the number 20 to find the optimal level for your case
            start()
        }else{
       print(totalRotation)
        }
    }

func start(){

//The function you want to trigger when the device is rotated

}