#define pir 4
#define led 18
int val=0;

void setup() {
Serial.begin(115200);
Serial.println("Hello, ESP321");
pinMode (pir, INPUT);
pinMode (led, OUTPUT);
}

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

if (val == 1){
digitalWrite(led,HIGH);
delay(1000);
}
else{
digitalWrite(led,LOW);
}
delay(100);
}