text: /*
   * Author: Jon Trulson <jtrulson@ics.com>
   * Copyright (c) 2015 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 <mraa/aio.h>
  
  namespace upm {
  
    /**
     * @brief OTP538U IR Temperature Sensor library
     * @defgroup otp538u libupm-otp538u
     * @ingroup seeed analog light hak
     */
    /**
     * @library otp538u
     * @sensor otp538u
     * @comname OTP538U IR Temperature Sensor
     * @altname Grove IR Temperature Sensor
     * @type light
     * @man generic
     * @con analog
     * @kit hak
     *
     * @brief API for the OTP538U IR Temperature Sensor
     *
     * UPM module for the OTP538U IR temperature sensor
     *
     * This module was tested with the Grove IR non-contact temperature
     * sensor.
     *
     * The sensor provides 2 analog outputs: one for the thermistor
     * that measures the ambient temperature, and the other for the thermopile
     * that measures the object temperature.
     *
     * Much of the code depends on analyzing Seeed Studio* examples
     * and the circuit design. As a result, there are several 'magic'
     * numbers derived from their circuit design. These values are used
     * by default.
     *
     * The tables used came from the "538U VT
     * Table__20_200(v1.3).pdf" and "538RT_table.pdf" datasheets.
     *
     * These tables assume the object to be measured is 9 cm (3.54
     * inches) from the sensor.
     *
     * This sensor will not work at 3.3v on the Edsion or the Galileo 2.
     * It works fine on both systems at 5v.  It will work at 3.3v on the
     * Arduino 101 (tested via firmata subplatform on edison).
     *
     * @image html otp538u.jpg
     * @snippet otp538u.cxx Interesting
     */
    class OTP538U {
    public:
      /**
       * OTP538U constructor
       *
       * @param pinA Analog pin to use for the ambient temperature
       * @param pinO Analog pin to use for the object temperature
       * @param aref Analog reference voltage; default is 5.0 V
       */
      OTP538U(int pinA, int pinO, float aref = 5.0);
  
      /**
       * OTP538U destructor
       */
      ~OTP538U();
  
      /**
       * Gets the ambient temperature in Celsius
       *
       * @return Ambient temperature
       */
      float ambientTemperature();
  
      /**
       * Gets the object temperature in Celsius
       *
       * @return Object temperature
       */
      float objectTemperature();
  
      /**
       * Sets the offset voltage
       *
       * The Seeed Studio wiki gives an example of calibrating the sensor
       * and calculating the offset voltage to apply. Currently, the
       * default value is set, but you can use the function to set one
       * of your own.
       *
       * @param vOffset Desired offset voltage
       */
      void setVoltageOffset(float vOffset) { m_offsetVoltage = vOffset; };
  
      /**
       * Sets the output resistance value
       *
       * The Seeed Studio wiki example uses a value of 2,000,000 in one of
       * the equations used to calculate voltage. The value is the
       * resistance of a resistor they use in the output stage of their
       * SIG2 output. This was 'decoded' by looking at the EAGLE* files
       * containing their schematics for this device.
       *
       * @param outResistance Value of the output resistor; default is 2M Ohm
       */
      void setOutputResistence(int outResistance) { 
        m_vResistance = outResistance; };
  
      /**
       * Sets the reference voltage of the internal Seeed Studio voltage
       * regulator on the sensor board.
       *
       * The Seeed Studio wiki example uses a value of 2.5 in one of the
       * equations used to calculate the resistance of the ambient
       * thermistor. The value is the voltage of an internal voltage
       * regulator used on the sensor board. This was 'decoded' by
       * looking at the EAGLE files containing their schematics for this
       * device.
       *
       * @param vref Reference voltage of the internal sensor; default
       * is 2.5
       */
      void setVRef(float vref) { m_internalVRef = vref; };
  
      /**
       * Enable debugging output.
       *
       * @param true to enable some debug output, false otherwise
       */
      void setDebug(bool enable) { m_debug = enable; };
  
  
    private:
      bool m_debug;
      float m_internalVRef;
      float m_aref;
      int m_vResistance;
      float m_offsetVoltage;
      int m_adcResolution;
      mraa_aio_context m_aioA;
      mraa_aio_context m_aioO;
    };
  }
  
  
  