int btn=2;
int led=11;
int buzzer=12;
int btnstate=0;
int ledstate=LOW;
void setup(){
  pinMode(btn, INPUT);
  pinMode(led, OUTPUT);
  pinMode(buzzer, OUTPUT);
  digitalWrite(led,ledstate);
}

void loop(){
  int btnstate1=digitalRead(btn);
  if (btnstate1 != btnstate){
    digitalWrite(buzzer, HIGH);
    delay(350);
    digitalWrite(led, HIGH);
  }
}