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/*
* Author: Jon Trulson <jtrulson@ics.com>
* Copyright (c) 2014 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 "groveehr.h"
using namespace upm;
using namespace std;
GroveEHR::GroveEHR(int pin)
{
if ( !(m_gpio = mraa_gpio_init(pin)) )
{
throw std::invalid_argument(std::string(__FUNCTION__) +
": mraa_aio_init() failed, invalid pin?");
return;
}
mraa_gpio_dir(m_gpio, MRAA_GPIO_IN);
initClock();
m_beatCounter = 0;
}
GroveEHR::~GroveEHR()
{
mraa_gpio_close(m_gpio);
}
void GroveEHR::initClock()
{
gettimeofday(&m_startTime, NULL);
}
uint32_t GroveEHR::getMillis()
{
struct timeval elapsed, now;
uint32_t elapse;
// get current time
gettimeofday(&now, NULL);
// compute the delta since m_startTime
if( (elapsed.tv_usec = now.tv_usec - m_startTime.tv_usec) < 0 )
{
elapsed.tv_usec += 1000000;
elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec - 1;
}
else
{
elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec;
}
elapse = (uint32_t)((elapsed.tv_sec * 1000) + (elapsed.tv_usec / 1000));
// never return 0
if (elapse == 0)
elapse = 1;
return elapse;
}
void GroveEHR::clearBeatCounter()
{
m_beatCounter = 0;
}
void GroveEHR::startBeatCounter()
{
// install our interrupt handler
mraa_gpio_isr(m_gpio, MRAA_GPIO_EDGE_RISING,
&beatISR, this);
}
void GroveEHR::stopBeatCounter()
{
// remove the interrupt handler
mraa_gpio_isr_exit(m_gpio);
}
uint32_t GroveEHR::beatCounter()
{
return m_beatCounter;
}
void GroveEHR::beatISR(void *ctx)
{
upm::GroveEHR *This = (upm::GroveEHR *)ctx;
This->m_beatCounter++;
}
int GroveEHR::heartRate()
{
uint32_t millis = getMillis();
uint32_t beats = beatCounter();
float heartRate = 0;
// wait at least 5 seconds before attempting to compute the
// heart rate
if (millis > 5000)
{
heartRate = (float(beats) / (float(millis) / 1000.0)) * 60.0;
}
return int(heartRate);
}
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