int led =12;
int sensorpin =2;
void setup()
{
pinMode (2, INPUT);
pinMode (12, OUTPUT);
Serial.begin(115200);
}
void loop()
{
  if(digitalRead(2)==LOW)
  {
    digitalWrite(12, HIGH);
    Serial.println("sensor detected"),
    delay(1000);
  }
  else
  {digitalWrite(12, LOW);
  Serial.println("sensor not detected");
  delay(1000);
  }
}