CALayer *layer = self.layer;
CAKeyframeAnimation *blinkAnim = [CAKeyframeAnimation animationWithKeyPath:@"opacity"];
blinkAnim.duration = 1.0;
//blinkAnim.repeatCount = 0;
blinkAnim.autoreverses = NO;

// keyframe times and values
// we want to start fully opaque, fade out, stay faded out and fade back in shortly before the end of the cycle
blinkAnim.keyTimes = [NSArray arrayWithObjects: [NSNumber numberWithFloat:0.0],
					  [NSNumber numberWithFloat:0.4],
					  [NSNumber numberWithFloat:0.6],
					  [NSNumber numberWithFloat:0.85],
					  [NSNumber numberWithFloat:1.0], nil];
blinkAnim.values = [NSArray arrayWithObjects:   [NSNumber numberWithFloat:1.0],
					[NSNumber numberWithFloat:1.0],
					[NSNumber numberWithFloat:0.0],
					[NSNumber numberWithFloat:0.0],
					[NSNumber numberWithFloat:0.5], nil];
[layer addAnimation:blinkAnim forKey:nil];

blinkAnim.removedOnCompletion = NO;
blinkAnim.fillMode = kCAFillModeForwards;