#define trig 25
#define echo 27
#define led 19
#define buzzer 17

long duration;
int distance;

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

void loop() {
  // put your main code here, to run repeatedly:
   // this speeds up the simulation
   digitalWrite(trig,LOW);
   delayMicroseconds(2);

   digitalWrite(trig,HIGH);
   delayMicroseconds(10);
   digitalWrite(trig,LOW);

   duration=pulseIn(echo,HIGH);
   distance=duration*0.034/2;

   Serial.print("distance is:");
   Serial.print(distance );
   Serial.print("cm");

   if(distance < 20){
    digitalWrite(led,HIGH);
    digitalWrite(buzzer,HIGH);
   }
   else{
    digitalWrite(led,LOW);
    digitalWrite(buzzer,LOW);
   }
   delay(200);
}