int trig=26;
int echo=27;
int distance;

void setup() {
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
  pinMode(23, OUTPUT);
  pinMode(22, OUTPUT);
  pinMode(21, OUTPUT);

  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
}

void loop() {
  digitalWrite(trig, HIGH);
  delay(100);
  digitalWrite(trig, LOW);
  int reading=pulseIn(echo,HIGH);
  distance=(reading*0.034/2)+1;
  Serial.println(distance);

  if(distance > 300)
  {
    digitalWrite(23, HIGH);
    digitalWrite(22, LOW);
    digitalWrite(21, LOW);
  }
  else if(distance>200)
  {
    digitalWrite(22, HIGH);
    digitalWrite(23, LOW);
    digitalWrite(21, LOW);
  }
  else 
  {
digitalWrite(21, HIGH);
digitalWrite(22, LOW);
digitalWrite(23, LOW);

  }
}