How to make a simple Motion Sensor Led Using Arduino

Arduino with PIR motion sensor
For complete project details, visit: http://RandomNerdTutorials.com/pirsensor
Modified by Rui Santos based on PIR sensor by Limor Fried
*/

int led = 13;                // the pin that the LED is attached to
int sensor = 2;              // the pin that the sensor is attached to
int state = LOW;             // by default, no motion detected
int val = 0;                 // variable to store the sensor status (value)

void setup() {
pinMode(led, OUTPUT);      // initialize LED as an output
pinMode(sensor, INPUT);    // initialize sensor as an input
Serial.begin(9600);        // initialize serial
}

void loop(){
val = digitalRead(sensor);   // read sensor value
if (val == HIGH) {           // check if the sensor is HIGH
digitalWrite(led, HIGH);   // turn LED ON
delay(100);                // delay 100 milliseconds

if (state == LOW) {
Serial.println(“Motion detected!”);
state = HIGH;       // update variable state to HIGH
}
}
else {
digitalWrite(led, LOW); // turn LED OFF
delay(200);             // delay 200 milliseconds

if (state == HIGH){
Serial.println(“Motion stopped!”);
state = LOW;       // update variable state to LOW
}
}
}