// INCLUDE ALL LIBRARIES
#include <DHT.h>
#include <ESP32Servo.h>
#include <Arduino.h>
#include <WiFi.h>
#include <WiFiMulti.h>
#include <HTTPClient.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <MQUnifiedsensor.h>

// DEFINE MQ135 to sens CO2
#define placa "ESP-32"
#define Voltage_Resolution 3.3
#define pin 0
#define type "MQ-135"
#define ADC_Bit_Resolution 12
#define RatioMQ135CleanAir 3.6
double CO2 = (0);
MQUnifiedsensor MQ135(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type);

void setup()
{
    MQ135.setRegressionMethod(1); //_PPM =  a*ratio^b
    MQ135.setA(110.47);
    MQ135.setB(-2.862);
    // Configurate the ecuation values to get NH4 concentration
    MQ135.init();
    Serial.print("Calibrating please wait.");
    float calcR0 = 0;
    for (int i = 1; i <= 10; i++)
    {
        MQ135.update(); // Update data, the arduino will be read the voltage on the analog pin
        calcR0 += MQ135.calibrate(RatioMQ135CleanAir);
        Serial.print(".");
    }
    MQ135.setR0(calcR0 / 10);
    Serial.println("  done!.");
    if (isinf(calcR0))
    {
        Serial.println("Warning: Conection issue founded, R0 is infite (Open circuit detected) please check your wiring and supply");
        while (1)
            ;
    }
    if (calcR0 == 0)
    {
        Serial.println("Warning: Conection issue founded, R0 is zero (Analog pin with short circuit to ground) please check your wiring and supply");
        while (1)
            ;
    }
    /*****************************  MQ CAlibration **************************/
    MQ135.serialDebug(false);
}

void loop()
{

    MQ135.update();           // Update data, the arduino will be read the voltage on the analog pin
    CO2 = MQ135.readSensor(); // Sensor will read CO2 concentration using the model and a and b values setted before or in the setup
    Serial.print("CO2: ");
    Serial.print(CO2);
}