int L1 =2;
int pause = 1000;
int btn = 7;

void setup() {

pinMode(L1, OUTPUT);
pinMode(btn, INPUT_PULLUP);
}
  
  void loop() { 

if(digitalRead(btn)== LOW) {
digitalWrite(L1, HIGH);
delay(pause);

}





digitalWrite(L1, LOW);
delay(pause);
  }