int lightPin = 4;
int sensorPin = 8;
int sensorState = LOW; // 0 , its off , assume



void setup() {
  pinMode(lightPin , OUTPUT);
  pinMode(sensorPin , INPUT);
  
  Serial.begin(9600);
}

void loop() {
int valueOfSensor = digitalRead(sensorPin); // HIGH or lOW , 1 or 0 , on or off

if(valueOfSensor == HIGH){
    digitalWrite(lightPin , HIGH);
    if(sensorState == LOW){
       Serial.println("Motion is detected");
       sensorState = HIGH;
    }
    // Serial.println("Motion is detected");
}
else{
  digitalWrite(lightPin , LOW);

  if(sensorState == HIGH){
    Serial.println("Motion has ended");
    sensorState = LOW;
  }
  
}

}