/*
 * 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-cooling-system-using-ds18b20-temperature-sensor
 */

 //Modified by Kishore Gaikwad, 23-Apr-2022

#include <Wire.h> 
#include <OneWire.h>
#include <DallasTemperature.h>
#include <LiquidCrystal_I2C.h>
#include <ThingSpeak.h>
#include <SPI.h>
#include <WiFi.h>
#include <FirebaseESP32.h>

LiquidCrystal_I2C lcd(0x27,16,2);
#define SECRET_SSID "MySSID"  // replace MySSID with your WiFi network name
#define SECRET_PASS "MyPass" // replace MyPass word with your WiFi password
#define SECRET_CH_ID 0000000                    // replace 0000000 with your channel number
#define SECRET_WRITE_APIKEY "XYZ" // replace XYZ with your channel write API Key

char ssid[] = SECRET_SSID; // your network SSID (name)
char pass[] = SECRET_PASS; // your network password

int keyIndex = 0;          // your network key Index number (needed only for WEP)
WiFiClient client;

unsigned long myChannelNumber = SECRET_CH_ID;
const char *myWriteAPIKey = SECRET_WRITE_APIKEY;

#define TEMP_UPPER_THRESHOLD  36 // upper temperature threshold
//#define TEMP_LOWER_THRESHOLD  34 // lower temperature threshold

#define MQ2pin 13
#define SENSOR_PIN     12  // ESP32 pin connected to DS18B20 sensor's DQ pin
#define RELAY_FAN_PIN  26 // ESP32 pin connected to relay
float sensorValue;  //variable to store sensor value

OneWire oneWire(SENSOR_PIN);
DallasTemperature DS18B20(&oneWire);

void setup() {
  Serial.begin(115200); // initialize serial
  DS18B20.begin();    // initialize the DS18B20 sensor
  pinMode(RELAY_FAN_PIN, OUTPUT);
  pinMode(MQ2pin, INPUT);
  lcd.begin();
  lcd.backlight();
  WiFi.mode(WIFI_STA);
  ThingSpeak.begin(client); // Initialize ThingSpeak
     
}

void loop() {
  // Connect or reconnect to WiFi
 if (WiFi.status() != WL_CONNECTED)
 {
   Serial.print("Attempting to connect to SSID: ");
   Serial.println(SECRET_SSID);
   while (WiFi.status() != WL_CONNECTED)
   {
     WiFi.begin(ssid, pass); // Connect to WPA/WPA2 network. Change this line if using open or WEP network
     Serial.print(".");
     delay(4000);
   }
   Serial.println("\nConnected.");
 }

  sensorValue = digitalRead(MQ2pin); // read analog input pin 0
  Serial.print("Sensor Value: ");
  Serial.print(sensorValue);
  Serial.print("\t");
  DS18B20.requestTemperatures();                  // send the command to get temperatures
  float temperature = DS18B20.getTempCByIndex(0); // read temperature in Celsius
  Serial.print(temperature);
  Serial.println("ºC");
  lcd.clear();
  lcd.setCursor(0, 0);                          // set cursor to first column, first row
  lcd.print(temperature);                   // print temp on lcd
  lcd.print((char)223); // display ° character
  lcd.print("C");
  
  
   if ((temperature > TEMP_UPPER_THRESHOLD)&& (sensorValue  > 200)){
    Serial.println("Turn the fan on");
    lcd.setCursor(0, 1);
    lcd.print("Turn the fan on");
    digitalWrite(RELAY_FAN_PIN, LOW); // turn on
  } else if ((temperature < TEMP_UPPER_THRESHOLD)&& (sensorValue  < 200)) {
    Serial.println("Turn the fan off");
    lcd.setCursor(0, 1);
    lcd.print("Turn the fan off");
    digitalWrite(RELAY_FAN_PIN, HIGH); // turn off
  }
  
   if ((temperature > TEMP_UPPER_THRESHOLD)|| (sensorValue  > 200)){
    Serial.println("Turn the fan on");
    lcd.setCursor(0, 1);
    lcd.print("Turn the fan on");
    digitalWrite(RELAY_FAN_PIN, LOW); // turn on
  } else if ((temperature < TEMP_UPPER_THRESHOLD)&& (sensorValue  < 200)) {
    Serial.println("Turn the fan off");
    lcd.setCursor(0, 1);
    lcd.print("Turn the fan off");
    digitalWrite(RELAY_FAN_PIN, HIGH); // turn off
  }

  delay(500);
    int x = ThingSpeak.writeField(myChannelNumber, 1,temperature, myWriteAPIKey); //dry atp temp
    int y = ThingSpeak.writeField(myChannelNumber, 2,sensorValue, myWriteAPIKey); //gas values
    
}