Code Library: B : Button-State-Counter

Button (switch) State Counter

const int buttonPin = 2;
const int ledPin = 13;

int buttonPushCounter = 0;
int buttonState = 0;
int lastButtonState = 0;

void setup()
{
  pinMode(buttonPin, INPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop()
{
  buttonState = digitalRead(buttonPin);

  if (buttonState != lastButtonState)
  {
    if (buttonState == HIGH)
    {
      buttonPushCounter++;
      Serial.println("on");
      Serial.print("number of button pushes: ");
      Serial.println(buttonPushCounter);
    }
    else
    {
      Serial.println("off");
    }
    delay(500);
  }
  if (buttonPushCounter % 4 == 0)
  {
    digitalWrite(ledPin, HIGH);
  }
  else
  {
    digitalWrite(ledPin, LOW);
  }
}