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

void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(pi, INPUT);
  pinMode(led, OUTPUT);
  }

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