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/*
* 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 <iostream>
#include <string>
#include <mraa/aio.hpp>
namespace upm {
/**
* @brief DFRobot pH sensors
* @defgroup dfrph libupm-dfrph
* @ingroup dfrobot liquid analog
*/
/**
* @library dfrph
* @sensor dfrph
* @comname DFRobot pH Sensors
* @type liquid
* @man dfrobot
* @web http://www.dfrobot.com/index.php?route=product/product&product_id=1110
* @con analog
*
* @brief API for the DFRobot pH Sensors
*
* This sensor family returns an analog voltage proportional to the
* acidity or alkalinity of a liquid -- it's pH value.
*
* This driver was developed using the DFRobot Analog pH meter and
* the DFRobot Analog pH Meter Pro.
*
*
* Calibration instructions, taken and slightly reworded from the
* DFRobot wiki at:
* http://dfrobot.com/wiki/index.php/PH_meter%28SKU:_SEN0161%29
*
* 1) Connect equipment: the pH electrode is connected to the BNC
* connector on the pH meter board, and then the pH meter board is
* connected to the analog port 0 of the controller. When the
* controller gets power, you will see the blue LED on board is on.
*
* 2) Put the pH electrode into the standard solution whose pH
* value is 7.00. Run the dfrph example and note the pH output
* value. Compare the value with 7.00, and calculate the
* difference. This is the value you should supply to the
* setOffset() method.
*
* 3) Put the pH electrode into the pH standard solution whose
* value is 4.00. Then wait about one minute, and adjust the
* potentiometer on the interface board. Let the value stabilise
* at around 4.00. At this time,the acidic calibration has been
* completed and you can measure the pH value of an acidic
* solution.
*
* 4) According to the linear characteristics of pH electrode
* itself, after the above calibration,you can directly measure the
* pH value of the alkaline solution. If you want to get better
* accuracy, you can recalibrate it. Alkaline calibration use the
* standard solution whose pH value is 9.18. Also adjust the
* potentiometer and let the value stabilise at around 9.18. After
* this calibration, you can measure the pH value of an alkaline
* solution.
*
* @image html dfrph.jpg
* @snippet dfrph.cxx Interesting
*/
class DFRPH {
public:
/**
* DFRPH constructor
*
* @param pin Analog pin to use
* @param aref Analog reference voltage; default is 5.0 V
*/
DFRPH(int pin, float aref=5.0);
/**
* DFRPH destructor
*/
~DFRPH();
/**
* Returns the voltage detected on the analog pin
*
* @return The detected voltage
*/
float volts();
/**
* Specifies the offset determined from calibration. The default
* is 0.0.
*
* @param offset The offset value to use
*/
void setOffset(float offset);
/**
* Take a number of samples and return the detected pH value. The
* default number of samples is 15.
*
* @param samples The number of samples to average over, default 15
* @return The pH value detected
*/
float pH(unsigned int samples=15);
protected:
mraa::Aio m_aio;
private:
float m_aref;
// ADC resolution
int m_aRes;
// voltage offset
float m_offset;
};
}
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