#define LED_PIN 3
#define PIR_PIN 4

int switchState = 0;
unsigned long lastTime = 0;
int intervalOn = 1000;

void setup() {
  pinMode(LED_PIN, OUTPUT);
  pinMode(PIR_PIN, INPUT);
}
void loop () {

  bool  motion = digitalRead(PIR_PIN);

  if (motion && !switchState) {
    switchState = motion;//remember
    digitalWrite(LED_PIN, HIGH);
  } else if (!motion && switchState) {
    if (millis() - lastTime >= intervalOn)
    {
      lastTime = millis();
      switchState = false;
      digitalWrite(LED_PIN, LOW);
    }
  }
}