text: /*
   * Author: Jon Trulson <jtrulson@ics.com>
   * Copyright (c) 2016 Intel Corporation.
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
   * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
   * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  #pragma once
  
  #include <string>
  #include <iostream>
  
  #include <mraa/aio.hpp>
  
  // Unlikey to be changable without external circuitry (voltage divider)
  #define CWLSXXA_DEFAULT_AREF 5.0
  
  namespace upm {
      /**
       * @brief Veris CWLSXXA CO2 Sensor
       * @defgroup cwlsxxa libupm-cwlsxxa
       * @ingroup veris ainput temp gaseous
       */
  
      /**
       * @library cwlsxxa
       * @sensor cwlsxxa
       * @comname Veris CWLSXXA CO2 Sensor Family
       * @type temp gaseous
       * @man veris
       * @con ainput
       * @web http://www.veris.com/Item/CWLSHTA.aspx
       *
       * @brief API for the Veris CWLSXXA CO2 Sensor Family
       *
       * The driver was developed using the CWLSHTA CO2 Gas sensor.  The
       * 'T' variant supports a temperature transmitter, and the 'H'
       * variant supports a humidity sensor.  All 3 signals are provided
       * by the device as analog 0-5Vdc, 0-10Vdc, or 4-20ma loop current
       * outputs.  For devices supporting temperature, the valid
       * temperature range is 10C to 50C.  The humidity ranges from 0%
       * to 100% (non-condensing).  The CO2 sensor ranges from 0 to 2000
       * ppm.
       *
       * This driver was developed using the 5Vdc outputs and the 4-20ma
       * outputs.  For voltage outputs, your MCU must be configured for
       * 5V operation.  In addition, you must configure the sensor (via
       * it's configuration switches) to output 0-5VDC only.  Using any
       * other analog reference voltage will require the appropriate
       * external circuitry (such as a voltage divider) in order to
       * interface safely with your MCU.
       *
       * In addition, the sensor can be configured for 4-20ma usage, by
       * specifying the correct receiver resistance (in ohms) in the
       * constructor.  This sensor was tested with a Cooking Hacks
       * (Libelium) 4-channel 4-20ma Arduino interface shield.  For this
       * interface, the receiver resistance was specified as 165.0 ohms.
       *
       * For devices which do not support temperature, use '-1' as the
       * temperature pin number in the object constructor.  If
       * temperature measurement is disabled, getTemperature() will always
       * return 0C/32F.
       *
       * For devices which do not support humidity, use '-1' as the
       * temperature pin number in the object constructor.  If
       * humidity measurement is disabled, getHumidity() will always
       * return 0.
       *
       * @snippet cwlsxxa.cxx Interesting
       */
  
    class CWLSXXA {
    public:
  
      /**
       * CWLSXXA object constructor
       *
       * @param gPin Analog pin to use for the CO2 measurement
       * @param hPin Analog pin to use for the humidity measurement.  If
       * your device does not support humidity, use -1 as the value so
       * that humidity will not be queried and an analog pin won't be
       * wasted.
       * @param tPin Analog pin to use for temperature.  If your device
       * does not support temperature, use -1 as the value so that
       * temperature will not be queried and an analog pin won't be
       * wasted.
       * @param rResistor The receiver resistance in ohms, when using a
       * 4-20ma current loop interface.  When specified, this value will
       * be used in computing the current based on the voltage read when
       * scaling the return values.  Default is 0.0, for standard
       * scaling based on voltage output rather than current (4-20ma
       * mode).
       * @param aref The analog reference voltage, default 5.0
       */
      CWLSXXA(int gPin, int hPin, int tPin, float rResistor=0.0,
              float aref=CWLSXXA_DEFAULT_AREF);
  
      /**
       * CWLSXXA object destructor
       */
      ~CWLSXXA();
  
      /**
       * Read current values from the sensor and update internal stored
       * values.  This method must be called prior to querying any
       * values, such as CO2, temperature, or humidity.
       */
      void update();
  
      /**
       * Get the current temperature.  update() must have been called
       * prior to calling this method.  If temperature measurement was
       * disabled (by passing -1 as the temperature pin in the
       * constructor) then this function will always return 0C/32F.
       *
       * @param fahrenheit true to return the temperature in degrees
       * fahrenheit, false to return the temperature in degrees celsius.
       * The default is false (degrees Celsius).
       * @return The last temperature reading in Celsius or Fahrenheit
       */
      float getTemperature(bool fahrenheit=false);
  
      /**
       * Get the current relative humidity.  update() must have been called
       * prior to calling this method. If humidity measurement was
       * disabled (by passing -1 as the te pin in the
       * constructor) then this function will always return 0.
       *
       * @return The last humidity reading
       */
      float getHumidity();
  
      /**
       * Get the current CO2 concentration in Parts Per Million (PPM).
       * update() must have been called prior to calling this method.
       *
       * @return The last CO2 reading
       */
      float getCO2();
  
  
    protected:
      // temperature and humidity are optional features of this transmitter
      mraa::Aio *m_aioTemp;
      mraa::Aio *m_aioHum;
  
      // CO2 reporting is always supported
      mraa::Aio m_aioCO2;
  
    private:
      float m_aref;
      float m_rResistor;
      int m_aResTemp;
      int m_aResHum;
      int m_aResCO2;
  
      // does this sensor support temperature and/or humidity reporting?
      bool m_hasTemp;
      bool m_hasHum;
  
      // in Celsius
      float m_temperature;
  
      float m_humidity;
  
      // in PPM
      float m_co2;
  
      int average(mraa::Aio *aio, int samples);
    };
  }
  
  
  