#include <WiFi.h>
#include <ThingSpeak.h>
#include <ESP32Servo.h>

#define TRIG_PIN 13
#define ECHO_PIN 12
#define GREEN_LED_PIN 14
#define YELLOW_LED_PIN 27
#define RED_LED_PIN 26
#define SERVO_PIN 25

const char* ssid = "Redmi";
const char* password = "Sgr2433046"; 

unsigned long myChannelNumber = 2581062; 
const char* myWriteAPIKey = "SDT2ITZADGY41Q4J";

WiFiClient client;
Servo myservo;

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(GREEN_LED_PIN, OUTPUT);
  pinMode(YELLOW_LED_PIN, OUTPUT);
  pinMode(RED_LED_PIN, OUTPUT);
  myservo.attach(SERVO_PIN);
  
  Serial.begin(9600);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("WiFi connected");

  ThingSpeak.begin(client);
}

void loop() {
  long duration, distance;
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN, HIGH);
  distance = 0.034*duration/2; 

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  
  if (distance < 100) { 
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, HIGH);
    myservo.write(180); 
  } else if (distance < 200) { 
    digitalWrite(GREEN_LED_PIN, LOW);
    digitalWrite(YELLOW_LED_PIN, HIGH);
    digitalWrite(RED_LED_PIN, LOW);
    myservo.write(90); 
  } else {
    digitalWrite(GREEN_LED_PIN, HIGH);
    digitalWrite(YELLOW_LED_PIN, LOW);
    digitalWrite(RED_LED_PIN, LOW);
    myservo.write(0); 
  }

  
  ThingSpeak.setField(1, distance);
  int x = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
  if(x == 200){
    Serial.println("Channel update successful.");
  }
  else{
    Serial.println("Problem updating channel. HTTP error code " + String(x));
  }

  delay(15000); 
}