1 /*
2 * Author: Jon Trulson <jtrulson@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
GroveEHR(int pin)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
~GroveEHR()49 GroveEHR::~GroveEHR()
50 {
51 mraa_gpio_close(m_gpio);
52 }
53
initClock()54 void GroveEHR::initClock()
55 {
56 gettimeofday(&m_startTime, NULL);
57 }
58
getMillis()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
clearBeatCounter()87 void GroveEHR::clearBeatCounter()
88 {
89 m_beatCounter = 0;
90 }
91
startBeatCounter()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
stopBeatCounter()99 void GroveEHR::stopBeatCounter()
100 {
101 // remove the interrupt handler
102 mraa_gpio_isr_exit(m_gpio);
103 }
104
beatCounter()105 uint32_t GroveEHR::beatCounter()
106 {
107 return m_beatCounter;
108 }
109
beatISR(void * ctx)110 void GroveEHR::beatISR(void *ctx)
111 {
112 upm::GroveEHR *This = (upm::GroveEHR *)ctx;
113 This->m_beatCounter++;
114 }
115
heartRate()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