Arduino ISR (Interrupt) Code Tutorial

I know a lot people look for something like this, so here is an example of how to debounce a button in an interrupt routine. this allows you to simply use the value in the main loop and not have to worry about the debouncing in the loop wasting time.

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volatile long lastDebounceTime = 0;   // the last time the interrupt was triggered
#define debounceDelay 50    // the debounce time in ms; decrease if quick button presses are ignored, increase
                             //if you get noise (multipule button clicks detected by the code when you only pressed it once)

#define BtnPin 0 //digital pin 2, interrupt 0

void setup()
{
  // put your setup code here, to run once:
  attachInterrupt(BtnPin,FireEvent, RISING);
  //this works on a switch that is pulled down to ground and sends V+ to the arduino pin when "closed" (pushed down)
  //See here for the scheme: http://arduino.cc/en/uploads/Tutorial/button_schem.png the resistor is 10k.
}

void loop()
{
  // put your main code here, to run repeatedly:
 
}

void FireEvent() //triggers when the switch is pressed. each time you press the switch,
{                //there are hundreds of little tiny conenctions as you press it down, so the delay filters those out.

  if ((millis() - lastDebounceTime) > debounceDelay) //if current time minus the last trigger time is greater than
  {                                                  //the delay (debounce) time, button is completley closed.
    lastDebounceTime = millis();
   
   //switch was pressed, do stuff like turn off your motor/led etc
  }
}
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