title: SpriteKit - Creating a timer
body: <p>How can I create a timer that fires every two seconds that will increment the score by one on a HUD I have on my screen? This is the code I have for the HUD:</p>
  
  <pre><code>    @implementation MyScene
  {
      int counter;
      BOOL updateLabel;
      SKLabelNode *counterLabel;
  }
  
  -(id)initWithSize:(CGSize)size
  {
      if (self = [super initWithSize:size])
      {
          counter = 0;
  
          updateLabel = false;
  
          counterLabel = [SKLabelNode labelNodeWithFontNamed:@"Chalkduster"];
          counterLabel.name = @"myCounterLabel";
          counterLabel.text = @"0";
          counterLabel.fontSize = 20;
          counterLabel.fontColor = [SKColor yellowColor];
          counterLabel.horizontalAlignmentMode = SKLabelHorizontalAlignmentModeCenter;
          counterLabel.verticalAlignmentMode = SKLabelVerticalAlignmentModeBottom;
          counterLabel.position = CGPointMake(50,50); // change x,y to location you want
          counterLabel.zPosition = 900;
          [self addChild: counterLabel];
      }
  }
  </code></pre>