#include <ESP32Servo.h>

#define TRIG_PIN  23  // ESP32 pin GIOP23 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN  22 // ESP32 pin GIOP22 connected to Ultrasonic Sensor's ECHO pin
#define SERVO_PIN 25  // ESP32 pin GIOP26 connected to Servo Motor's pin
#define DISTANCE_THRESHOLD  150 // centimeters
//#define DISTANCE_THRESHOLD2  300 // centimeters
#define LED_PIN 18

Servo servo; // create servo object to control a servo

// variables will change:
float duration_us, distance_cm;

void setup() {
  Serial.begin (9600);       // initialize serial port
  Serial.println ("Welcome To Distance Meter");
  Serial.println ("Coded By Harshini");
  pinMode(TRIG_PIN, OUTPUT); // set ESP32 pin to output mode
  pinMode(ECHO_PIN, INPUT);  // set ESP32 pin to input mode
  servo.attach(SERVO_PIN);   // attaches the servo on pin 9 to the servo object
  pinMode(LED_PIN, OUTPUT);
  servo.write(90);
}

void loop() {
  // generate 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // measure duration of pulse from ECHO pin
  duration_us = pulseIn(ECHO_PIN, HIGH);
  // calculate the distance
  distance_cm = 0.017 * duration_us;

  if (distance_cm < DISTANCE_THRESHOLD)
  {
    servo.write(180);
    digitalWrite(18, HIGH);
    //delay(2000);
  }

  if (distance_cm > DISTANCE_THRESHOLD)
  {
    servo.write(0);
    digitalWrite(18, LOW);
    //delay(2000);
  }

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

delay(500);

}