const int trigPin = 13;
const int echoPin = 12;
const int ledGreen = 15;
const int ledBuzz = 2;
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701
long duration;
float distanceCm;
float distanceInch;
void setup() {
  Serial.begin(115200);
  Serial.println("Hello, ESP321");
  Serial.begin(115200);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(ledGreen, OUTPUT);
  pinMode(ledBuzz, OUTPUT);
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(10);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration= pulseIn(echoPin,HIGH);
  distanceCm = duration * SOUND_SPEED/2;
  distanceInch = distanceCm * CM_TO_INCH;
  Serial.print("Distance(cm):");
  Serial.println(distanceCm);
  Serial.print("Distance(inch):");
  Serial.println(distanceInch);
  if(distanceCm <10)
  {
    digitalWrite(ledGreen,LOW);
    digitalWrite(ledBuzz, LOW );
  }
  else if(distanceCm<40)
  {
    digitalWrite(ledGreen,HIGH);
    digitalWrite(ledBuzz, LOW );
  }
  else if(distanceCm<70)
  {
    digitalWrite(ledGreen,HIGH);
    digitalWrite(ledBuzz, HIGH);
  }
  else
  {
    digitalWrite(ledGreen,LOW);
    digitalWrite(ledBuzz, LOW );
  }
}