#define pir 7
int val=0,state=LOW;

void setup() 
{
  Serial.begin(9600);
  pinMode(pir, INPUT);
}

void loop() 
{
  val=digitalRead(pir);

  if(val==HIGH)
  {
    if(state==LOW)
    {
      Serial.println("Motion Occured");
      state=HIGH;
    }
  }
  else
  {
    if(state==HIGH)
    {
      Serial.println("Motion Ended");
      state=LOW;
    }
  }

}