text: #ifndef CO2_MG811_h
  #define CO2_MG811_h
  
  #include <Arduino.h>
  
  namespace AnalogSensor {
  class CO2_MG811
  {
    public:
      /**
       * Constructor
       */
      CO2_MG811(int pin);
      
      /**
       * Constructor
       */
      CO2_MG811(int pin, float inertia, int tries);
      
      /**
       * Returns the PPM concentration
       */
      int read();
  
      /**
       * Calibrates the start point of 400
       */    
      void calibrate();
  
      /**
       * Returns the voltage
       */
      int getVoltage();
    private:
      /**
       * Internal initialization
       */
      void init();
  
      int _pin;
      int _inertia;
      int _tries;
      int _co2_v;
      
      double _co2_a;
      double _co2ppm;
  };
  }
  #endif