upm/src/grove/grovetemp.cxx
Mihai Tudor Panu bda66a3d06 grovetemp: updated conversion formula for v1.2 compatibility
Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>
2016-08-02 10:16:46 -07:00

69 lines
2.2 KiB
C++

/*
* Authors: Brendan Le Foll <brendan.le.foll@intel.com>
* Mihai Tudor Panu <mihai.tudor.panu@intel.com>
* Sarah Knepper <sarah.knepper@intel.com>
* Copyright (c) 2014 - 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.
*/
#include <iostream>
#include <string>
#include <stdexcept>
#include "grovetemp.hpp"
#include "math.h"
using namespace upm;
GroveTemp::GroveTemp(unsigned int pin, float scale, int r0, int b)
{
if ( !(m_aio = mraa_aio_init(pin)) ) {
throw std::invalid_argument(std::string(__FUNCTION__) +
": mraa_aio_init() failed, invalid pin?");
return;
}
m_name = "Temperature Sensor";
m_scale = scale;
m_r0 = r0;
m_b = b;
}
GroveTemp::~GroveTemp()
{
mraa_aio_close(m_aio);
}
int GroveTemp::value ()
{
float a = (float) mraa_aio_read(m_aio);
if (a == -1.0) return -1;
// Apply scale factor after error check
a *= m_scale;
float r = (float)(1023.0-a)*(float)m_r0/a;
float t = 1.0/(log(r/(float)m_r0)/(float)m_b + 1.0/298.15)-273.15;
return (int) round(t);
}
float GroveTemp::raw_value()
{
return (float) mraa_aio_read(m_aio);
}