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      1 /*
      2  * Author: Jon Trulson <jtrulson (at) ics.com>
      3  * Copyright (c) 2014 Intel Corporation.
      4  *
      5  * Permission is hereby granted, free of charge, to any person obtaining
      6  * a copy of this software and associated documentation files (the
      7  * "Software"), to deal in the Software without restriction, including
      8  * without limitation the rights to use, copy, modify, merge, publish,
      9  * distribute, sublicense, and/or sell copies of the Software, and to
     10  * permit persons to whom the Software is furnished to do so, subject to
     11  * the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be
     14  * included in all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     17  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     18  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     19  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     20  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     21  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     22  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     23  */
     24 
     25 #include <iostream>
     26 #include <string>
     27 #include <stdexcept>
     28 
     29 #include "groveehr.h"
     30 
     31 using namespace upm;
     32 using namespace std;
     33 
     34 GroveEHR::GroveEHR(int pin)
     35 {
     36   if ( !(m_gpio = mraa_gpio_init(pin)) )
     37     {
     38       throw std::invalid_argument(std::string(__FUNCTION__) +
     39                                   ": mraa_aio_init() failed, invalid pin?");
     40       return;
     41     }
     42 
     43   mraa_gpio_dir(m_gpio, MRAA_GPIO_IN);
     44 
     45   initClock();
     46   m_beatCounter = 0;
     47 }
     48 
     49 GroveEHR::~GroveEHR()
     50 {
     51   mraa_gpio_close(m_gpio);
     52 }
     53 
     54 void GroveEHR::initClock()
     55 {
     56   gettimeofday(&m_startTime, NULL);
     57 }
     58 
     59 uint32_t GroveEHR::getMillis()
     60 {
     61   struct timeval elapsed, now;
     62   uint32_t elapse;
     63 
     64   // get current time
     65   gettimeofday(&now, NULL);
     66 
     67   // compute the delta since m_startTime
     68   if( (elapsed.tv_usec = now.tv_usec - m_startTime.tv_usec) < 0 )
     69     {
     70       elapsed.tv_usec += 1000000;
     71       elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec - 1;
     72     }
     73   else
     74     {
     75       elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec;
     76     }
     77 
     78   elapse = (uint32_t)((elapsed.tv_sec * 1000) + (elapsed.tv_usec / 1000));
     79 
     80   // never return 0
     81   if (elapse == 0)
     82     elapse = 1;
     83 
     84   return elapse;
     85 }
     86 
     87 void GroveEHR::clearBeatCounter()
     88 {
     89   m_beatCounter = 0;
     90 }
     91 
     92 void GroveEHR::startBeatCounter()
     93 {
     94   // install our interrupt handler
     95   mraa_gpio_isr(m_gpio, MRAA_GPIO_EDGE_RISING,
     96                 &beatISR, this);
     97 }
     98 
     99 void GroveEHR::stopBeatCounter()
    100 {
    101   // remove the interrupt handler
    102   mraa_gpio_isr_exit(m_gpio);
    103 }
    104 
    105 uint32_t GroveEHR::beatCounter()
    106 {
    107   return m_beatCounter;
    108 }
    109 
    110 void GroveEHR::beatISR(void *ctx)
    111 {
    112   upm::GroveEHR *This = (upm::GroveEHR *)ctx;
    113   This->m_beatCounter++;
    114 }
    115 
    116 int GroveEHR::heartRate()
    117 {
    118   uint32_t millis = getMillis();
    119   uint32_t beats = beatCounter();
    120 
    121   float heartRate = 0;
    122   // wait at least 5 seconds before attempting to compute the
    123   // heart rate
    124   if (millis > 5000)
    125     {
    126       heartRate = (float(beats) / (float(millis) / 1000.0)) * 60.0;
    127     }
    128 
    129   return int(heartRate);
    130 }
    131