int buzzerPin = 7; // define the buzzer pin
int wirePin = 2; // define the wire pin

void setup() {
  pinMode(buzzerPin, OUTPUT);
  pinMode(wirePin, INPUT);
  Serial.begin(9600);
}

void loop() {
  if (digitalRead(wirePin) == HIGH) { // if loop touches the wire
    digitalWrite(buzzerPin, HIGH); // turn on the buzzer
    delay(500); // wait for 500ms
    digitalWrite(buzzerPin, LOW); // turn off the buzzer
  }
}