int ledPin = 13;               
int inputPin = 3;               
int val = 0;                    
void setup() {
  pinMode(ledPin, OUTPUT);      
  pinMode(inputPin, INPUT);     
  Serial.begin(9600);
}
void loop() {
  val = digitalRead(inputPin);  
  if (val == HIGH) {            
    digitalWrite(13, HIGH);  
    Serial.println("Motion is detected!");
  } 
  else {
    digitalWrite(13, LOW); 
    Serial.println("Motion ended!");
    }
}