#include <ESP32Servo.h>

#define TRIG_PIN 32 // ESP32 pin GIOP23 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN 35 // ESP32 pin GIOP22 connected to Ultrasonic Sensor's ECHO pin
#define SERVO_PIN 13 // ESP32 pin GIOP26 connected to Servo Motor's pin
#define DISTANCE_THRESHOLD 200  // centimeters
#define red 21
#define blue 19


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

// variables will changes:
float duration_us, Distance_cm;

void setup(){
  Serial.begin (9600); // intialize serial port
  Serial.println ("Welcome To Distance Meter");
  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 12 to the servo object
  pinMode(red, OUTPUT);
  pinMode(blue, OUTPUT);
 
  servo.write(180);
}

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 = 0.0017 * duration_us;

  if (Distance_cm < 25)
  {
    servo.write(0);
  
    digitalWrite(red, HIGH);
    digitalWrite(blue, LOW);
    delay(250);
    digitalWrite(red, LOW);
    digitalWrite(blue, HIGH);
  
    //delay(2000);
  }

  if (Distance_cm > 25)
  {
    servo.write(180);
 
    digitalWrite(red, LOW);
    digitalWrite(blue, HIGH);
  
    //delay(2000);
  }


  // print the value tp Serial Monitor
  Serial.print("Distance= ");
  Serial.print(Distance_cm);
  Serial.println(" cm");

delay(500); 
}