#include <ESP32Servo.h>
#include <DHT.h>

#define TRIG 5
#define ECHO 18
#define DHTPIN 15
#define DHTTYPE DHT22
#define GAS 34
#define PIR 23

#define LED 2
#define BUZZER 4
#define SERVO_PIN 19

Servo myServo;
DHT dht(DHTPIN, DHTTYPE);

long duration;
int distance;
int gasValue;
int pirState;
float temp;

void setup() {

  ESP32PWM::allocateTimer(0);
  ESP32PWM::allocateTimer(1);
  ESP32PWM::allocateTimer(2);
  ESP32PWM::allocateTimer(3);

  Serial.begin(115200);

  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(PIR, INPUT);
  pinMode(LED, OUTPUT);
  pinMode(BUZZER, OUTPUT);

  myServo.setPeriodHertz(50);
  myServo.attach(SERVO_PIN, 500, 2400);

  dht.begin();
}

void loop() {

  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);
  duration = pulseIn(ECHO, HIGH);
  distance = duration * 0.034 / 2;

  temp = dht.readTemperature();
  gasValue = analogRead(GAS);
  pirState = digitalRead(PIR);

  if (distance < 20 || temp > 30 || gasValue > 2000 || pirState == HIGH) {

    for (int i = 0; i <= 90; i++) {
      myServo.write(i);
      digitalWrite(LED, HIGH);
      digitalWrite(BUZZER, HIGH);
      delay(15);
    }

  } else {
    digitalWrite(LED, LOW);
    digitalWrite(BUZZER, LOW);
    myServo.write(0);
  }

  delay(1000);
}