#define TRIG_PIN   23 // ESP32 pin GPIO26 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN   22 // ESP32 pin GPIO25 connected to Ultrasonic Sensor's ECHO pin
#define BUZZER_PIN 2 // ESP32 pin GPIO17 connected to Piezo Buzzer's pin
#define DISTANCE_THRESHOLD 50 // centimeters
#define BLYNK_TEMPLATE_ID "TMPL3_FleMzYg"
#define BLYNK_TEMPLATE_NAME "SATHISH"
#define BLYNK_AUTH_TOKEN "arwdK8H1mq0x2iAEromnyjIeDBNduBg1"
#include<WiFi.h>
#include<WiFiClient.h>
#include <BlynkSimpleEsp32.h>
#include<NewPing.h>
// variables will change:
float duration_us, distance_cm;
char ssid[]="Wokwi-GUEST";
char pass[]="";
char auth[]="arwdK8H1mq0x2iAEromnyjIeDBNduBg1";

void setup() {
  Serial.begin (10000);         // initialize serial port
  pinMode(TRIG_PIN, OUTPUT);   // set ESP32 pin to output mode
  pinMode(ECHO_PIN, INPUT);    // set ESP32 pin to input mode
  pinMode(BUZZER_PIN, OUTPUT); // set ESP32 pin to output mode
}

void loop() {
  // generate 2-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, LOW);

  // measure duration of pulse from ECHO pin
  duration_us = pulseIn(ECHO_PIN, HIGH);
  // calculate the distance
  distance_cm = 0.01 * duration_us;

  if (distance_cm < DISTANCE_THRESHOLD)
    digitalWrite(BUZZER_PIN, HIGH); // turn on Piezo Buzzer
  else
    digitalWrite(BUZZER_PIN, LOW);  // turn off Piezo Buzzer

  // print the value to Serial Monitor
  Serial.print("distance: ");
  Serial.print(distance_cm);
  Serial.println(" cm");

  delay(1000);
}