shake.m

// Inherit your main window from this custom class:

@implementation MotionWindow

- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {
    if (event.type == UIEventTypeMotion && event.subtype == UIEventSubtypeMotionShake) {
		NSLog(@"Global Shake!");
        [[NSNotificationCenter defaultCenter] postNotificationName:@"DeviceShaken" object:self];
    }
}

@end


// Then in any view controller:

- (void)deviceShaken {
	if(inShake) {
//		NSLog(@"in shake. skip");
		return;
	}
	NSTimeInterval newTimeOfShake = [[NSDate date] timeIntervalSince1970];
	if(newTimeOfShake - timeOfShake < 1 && timeOfShake != 0){
//		NSLog(@"too soon shake. skip");
		return; 
	}
	timeOfShake = newTimeOfShake;


// ============== add your code here ==========
	inShake = NO;
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
	[[NSNotificationCenter defaultCenter] addObserver:self											                        
                         selector:@selector(deviceShaken) name:@"DeviceShaken" object:nil];

}


- (void)viewDidDisappear:(BOOL)animated {
	[super viewDidDisappear:animated];
	[[NSNotificationCenter defaultCenter] removeObserver:self];
}