by Ted Hayes, from code originally by Alexander Brevig & Tom Igoe

The Arduino Button library makes it easy to do some very common but rather tedious tasks. Usually when you interact with a button (such as a momentary switch), you mainly want to detect the state change, not just the current state. You have to do something like:

int lastState = 0;

void loop(){
	int currentState = digitalRead(11);
	if(currentState != lastState){
		// do something
	}
	lastState = currentState;
}

It's not hard, just tedious. This new and improved Button library makes this much simpler but adds so much more. Now you can do it this way:

Button button = Button(12);

void onPress(Button& b){
	Serial.print("onPress: ");
	Serial.println(b.pin);
	// will print out "onPress: 12"
}

void setup(){
  Serial.begin(9600);
  // Assign callback function
  button.pressHandler(onPress);
}

void loop(){
  // update the buttons' internals
  button.process();
}

• Instance-based design

  Button myButton(11);

• Automatic pull-up setting

  Button myButton(11, BUTTON_PULLUP_INTERNAL);

• Simplified state-change detection:

  if(button.isPressed()) ...

• Callback model

  button.pressHandler(onPress)

• Built-in debouncing

  // Sets 50ms debounce duration

  Button button = Button(12, BUTTON_PULLUP_INTERNAL, true, 50);

To install, download the library, extract it to ~/Documents/Arduino/libraries and rename the folder "Button." (Github generates a different name for the zip link.) Restart Arduino if it was already open.

I hope you find this useful! Please report any bugs using the Github issue tracker.