bool latch = false;

void setup(){
pinMode(1, INPUT);
pinMode(13, OUTPUT);
}
void loop(){
if (digitalRead(1)){
  latch = true;
}else{
latch = false;
}
if (latch){
  digitalWrite(13, HIGH);
  delay(1000);
  digitalWrite(13, LOW);
  delay(1000);
}else{
  digitalWrite(13, LOW);
}

}