int buttonState = 0;         // variable for reading the pushbutton status

void setup() {
  // initialize the LED pin as an output:
  pinMode(A2, OUTPUT);
  // initialize the pushbutton pin as an input:
  pinMode(8, INPUT);
}

void loop() 
  {
    buttonState = digitalRead(8);   //asignamos un valor
    if (buttonState == HIGH) //comparamos el estado del boton con el valor HIGH
    
    // turn LED on:     
    digitalWrite(A2, HIGH);
    
      else
      
        // turn LED off
        
        digitalWrite(A2,LOW);
    }