#define D2 2
#define D12 12
void setup()
{
pinMode(D2, OUTPUT);
pinMode(D12, INPUT_PULLUP);
digitalWrite(D2, LOW);

}
void loop()
{
  if(digitalRead(D12)==LOW)
  {
    digitalWrite(D2, HIGH);
    delay(1000);
  }
  else digitalWrite(D2, LOW);
}