/*
 * This ESP32 code is created by esp32io.com
 *
 * This ESP32 code is released in the public domain
 *
 * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-ultrasonic-sensor-servo-motor
 */

#include <ESP32Servo.h>

#define TRIG_PIN  23  // ESP32 pin GPIO23 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN  22  // ESP32 pin GPIO22 connected to Ultrasonic Sensor's ECHO pin
#define TRIG_PIN1  17  // ESP32 pin GPIO23 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN1  16  // ESP32 pin GPIO22 connected to Ultrasonic Sensor's ECHO pin
#define SERVO_PIN 26  // ESP32 pin GPIO26 connected to Servo Motor's pin
//#define BUTTON_PIN 27
#define LED_PIN 14
#define DISTANCE_THRESHOLD  60 // centimeters

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

// variables will change:
float duration_us, distance_cm, duration_us1, distance_cm1;
//int led_state = LOW;    // the current state of LED
//int button_state;       // the current state of button
//int last_button_state;  // the previous state of button



void setup() {
  Serial.begin (9600);       // initialize serial port
  pinMode(LED_PIN, OUTPUT);
  //pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(TRIG_PIN, OUTPUT); // set ESP32 pin to output mode
  pinMode(ECHO_PIN, INPUT);  // set ESP32 pin to input mode
  pinMode(TRIG_PIN1, OUTPUT); // set ESP32 pin to output mode
  pinMode(ECHO_PIN1, INPUT);  // set ESP32 pin to input mode
  servo.attach(SERVO_PIN);   // attaches the servo on pin 9 to the servo object
  servo.write(0);
}

void loop() {
  // generate 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  digitalWrite(TRIG_PIN1, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  digitalWrite(TRIG_PIN1, LOW);

  // digitalWrite(TRIG_PIN1, HIGH);
  // delayMicroseconds(10);
  // digitalWrite(TRIG_PIN1, LOW);

  //last_button_state = button_state;      // save the last state
  //button_state = digitalRead(BUTTON_PIN); // read new state

  // measure duration of pulse from ECHO pin
  duration_us = pulseIn(ECHO_PIN, HIGH);
  duration_us1 = pulseIn(ECHO_PIN1, HIGH);
  // calculate the distance
  distance_cm = 0.017 * duration_us;
  distance_cm1 = 0.017 * duration_us1;

  if ((distance_cm  < DISTANCE_THRESHOLD) && (distance_cm1 < DISTANCE_THRESHOLD)){
    servo.write(90); // rotate servo motor to 90 degree
    digitalWrite(LED_PIN, HIGH);
  }
  else{
    servo.write(0);  // rotate servo motor to 0 degree
    digitalWrite(LED_PIN, LOW);

  }

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

  delay(500);
}