const int BUTTON_PIN = 27;     // the number of the pushbutton pin
const int VACUUM_PIN =  26;      // the number of the pump pin (28 for pump, 26 for LED)

int buttonState = 0;         // variable for reading the pushbutton status
bool lastButtonState = LOW;
bool pumpState = LOW;

void setup() {
  pinMode(VACUUM_PIN, OUTPUT);      // pump is defined as output
  pinMode(BUTTON_PIN, INPUT);    // pushbutton is defined as input
  Serial.begin(9600);
}

void loop() {
  // read button status
  int reading = digitalRead(BUTTON_PIN);
  // check if button status changed
  if (reading != lastButtonState) {
    if (reading == HIGH) {
      //change pump state
      pumpState = !pumpState;
      digitalWrite(VACUUM_PIN, pumpState); 
      Serial.print("pump state is ");
      Serial.println(pumpState ? "open" : "off");
    }
  }
  
  lastButtonState = reading;
}