#define BLYNK_TEMPLATE_ID "TMPL3aTWCznVV"
#define BLYNK_TEMPLATE_NAME "virtual reality navigation  for visually impaired"
#define BLYNK_AUTH_TOKEN "EVVY9zP0bSUc177niLTOOuNeufKI8Ytt"
//code using ultrasonic sensor with ESP32
#define trigPin 13
#define echoPin 12
#define buzzerpin 18 //define the pin connected to the buzzer
void setup() {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin,   INPUT);
  pinMode(buzzerpin,OUTPUT); // set the buzzer pin as an output
}

void loop() {
  long duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  Serial.print("Distance: ");
  Serial.println(distance);
  delay(1000);
  Serial.println("CM");
  if((distance<=10))
  {
    tone(buzzerpin,1000); //set the buzzer as an output
    delay(500); //wait for 500 milliseconds
  }
  else
  {
    noTone(buzzerpin); //stop the tone
    delay(500); //wait for 500 milliseconds
  }
}