void setup()
{
  pinMode(18,INPUT);
  pinMode(16, OUTPUT);
  Serial.begin(9600);
}
void loop()
{
  int motion=0;
  motion = digitalRead(18);
  if(motion==HIGH)
  {
    digitalWrite(16, HIGH);
    Serial.println(motion);
    Serial.println("motion detected");
  }
  else
  {
    digitalWrite(16, LOW);
    Serial.println(motion);
    Serial.println("motion not detected");
  }
  delay(1000);
}