Handling multiple states is one of the keystones of programming. In this example we use one button to cycle through 3 LEDs. This gives us a 4 states (all off, red,green,yellow). By passing the state between variables we can cycles through them with ease. This example uses the button debouncing code that was described in this video:
   • How to debounce a button for Arduino  

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   • 10 PCB's for two bucks!  
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