có cảm biến gas

#include<LiquidCrystal.h>
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);
int motorPin = 12;        //connection pins of DC motor
int temp = 0;             //value variable temp
int r =0;                
float voltage = 0;        //value variable voltage
float sensor = 0;         //value variable sensor
float celsius = 0;        //value variable celsius(C)
float fahrenheit = 0;     //value variable fahrenheit(F)
int couter = 0;           //couter variable
int sensor_In = 0;        //smoke sensor
#define SENSOR_PIN A1     //sensor connector
void setup()
{
  Serial.begin(9600);   //Open the Serial port at baudrate 9600 to communicate with the computer
  pinMode(2, INPUT);    //Cài đặt chân D2 ở trạng thái đọc dữ liệu
  pinMode(2,OUTPUT);
  //lcd.setCursor(3,0);
  //lcd.print("NHIET DO");
  pinMode(A1, INPUT);
  lcd.begin(16, 2);       //LCD screen with size 16x2.
  pinMode(13, OUTPUT);    //13 is the output (OUTPUT) to drive the LED and the DC motor.
  pinMode(12, OUTPUT);    //12 is the output (OUTPUT) to drive the LED
  //Setup DC motor
  //pinMode(motorPin, OUTPUT);
   while (!Serial);       //The program will execute this print command line and then execute other commands
   Serial.println("Speed 0 to 255");
}
void loop()
{  
  sensor_In = analogRead(A0);         //read smoke sensor using analogRead(A0)  
  temp = analogRead(A1);              //read temperature sensor using analogRead(A1)
  Serial.println(analogRead(A0));     //Write the value you just read to Serial and print it on the computer
  Serial.println(analogRead(A1));     //Write the value you just read to Serial and print it on the computer
  lcd.setCursor(5,1);                 //cursor is displayed in column 5 and row 1
  for (int i = 12; i <= 13; i++)      //turn off output on two ports 12 and 13
      digitalWrite(i, LOW);         
 if (temp >= 207 ||sensor_In >=30) 	  //Check temperature value and smoke sensor.
  {
    digitalWrite(13, HIGH);           //Turn on the LED on pin 13  
    digitalWrite(12, LOW);            //Turn off the LED on pin 12.
    tone(13, 720);                    //play tone 60 (C5 = 523 Hz)
    sensor = analogRead(SENSOR_PIN);  //Read the value from the sensor and calculate the Celsius temperature value.
  	voltage = (sensor*5000)/1024;     //mV (mili Volt).
  	voltage = voltage-495;
  	celsius = voltage/10;             //convert voltage value to Celsius . temperature unit
    lcd.setCursor(6,0);
    lcd.print(celsius);
    lcd.setCursor(2,4);
    lcd.print("Co 1 dam chay");
    delay(1000);
    lcd.clear();   	
  }
  else if(temp <207 || sensor_In < 30){
  	digitalWrite(13, LOW);
    digitalWrite(12, HIGH);
    lcd.clear();
    noTone(13);
    sensor = analogRead(SENSOR_PIN);
  	voltage = (sensor*5000)/1024; //5000mv chia cho giá trị analog
  	voltage = voltage-495;        // trừ điện áp bù trừ
  	celsius = voltage/10;         // chuyển từ mV sang độ C
   	lcd.setCursor(6,0);
    lcd.print(celsius);           // giá trị C hiển thị ở dòng thứ 3
   	lcd.setCursor(3,4);
    lcd.print("Binh Thuong");
    delay(1000);
    lcd.clear();
    delay(1000);
  } 
}