void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(18, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(2, OUTPUT);
  pinMode(19, INPUT);
}

void loop() 
{
 digitalWrite(18, HIGH);   // LED padam
 digitalWrite(5, HIGH);   // LED padam
 digitalWrite(4, HIGH);   // LED padam
 digitalWrite(2, HIGH);   // LED padam
 delay(500);                     // tunggu 1 detik
 digitalWrite(18, LOW);   // LED menyala
 digitalWrite(5, LOW);   // LED menyala
 digitalWrite(4, LOW);   // LED menyala
 digitalWrite(2, LOW);   // LED menyala
 delay(500);  
}