void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
  pinMode(25, OUTPUT);
  pinMode(12, INPUT);
}

void loop() {
  
  digitalWrite(25, HIGH);
  delay(1000);
  digitalWrite(25, LOW);
  int duration = pulseIn(12,HIGH);
  int distance = duration*034/2;
  Serial.println("distance");
  Serial.println(distance);
}