void setup() {

    const int ledPin = 13;

    const int pirPin = 2;

    pinMode(ledPin, OUTPUT);

    pinMode(pirPin, INPUT);
}

void loop() {

    int pirState = digitalRead(pirPin);
    
    if (pirState == HIGH) {

        digitalWrite(ledPin, HIGH);

    } else {

        digitalWrite(ledPin, LOW);
    }
}