upm/src/dfrph/dfrph.cxx

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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.
*/
#include <iostream>
#include "dfrph.h"
using namespace std;
using namespace upm;
DFRPH::DFRPH(int pin, float aref) :
m_aio(pin)
{
m_aRes = (1 << m_aio.getBit());
m_aref = aref;
m_offset = 0.0;
}
DFRPH::~DFRPH()
{
}
float DFRPH::volts()
{
int val = m_aio.read();
return(val * (m_aref / m_aRes));
}
void DFRPH::setOffset(float offset)
{
m_offset = offset;
}
float DFRPH::pH(unsigned int samples)
{
if (!samples)
samples = 1;
float sum = 0.0;
for (int i=0; i<samples; i++)
{
sum += volts();
usleep(20000);
}
sum /= samples;
// 3.5 is a 'magic' DFRobot number. Seems to work though :)
return (3.5 * sum + m_offset);
}