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ppd42ns: C implementation; C++ wraps C

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Signed-off-by: Jon Trulson <jtrulson@ics.com>
This commit is contained in:
Jon Trulson
2016-11-02 17:38:44 -06:00
parent 8f6442e9c7
commit 1f954a8cbf
13 changed files with 467 additions and 194 deletions
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108
src/ppd42ns/ppd42ns.cxx
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@@ -1,6 +1,7 @@
/*
* Author: Zion Orent <sorent@ics.com>
* Copyright (c) 2014 Intel Corporation.
* Jon Trulson <jtrulson@ics.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
@@ -25,113 +26,26 @@
#include <iostream>
#include <string>
#include <stdexcept>
#include <stddef.h>
#include <stdio.h>
#include <time.h>
#include <math.h>
#include <sys/sysinfo.h>
#include "ppd42ns.hpp"
using namespace upm;
PPD42NS::PPD42NS(int pin)
PPD42NS::PPD42NS(int pin) :
m_ppd42ns(ppd42ns_init(pin))
{
if ( !(m_gpio = mraa_gpio_init(pin)) )
{
throw std::invalid_argument(std::string(__FUNCTION__) +
": mraa_gpio_init() failed, invalid pin?");
return;
}
mraa_gpio_dir(m_gpio, MRAA_GPIO_IN);
if (!m_ppd42ns)
throw std::runtime_error(std::string(__FUNCTION__) +
": ppd42ns_init() failed");
}
PPD42NS::~PPD42NS()
{
mraa_gpio_close(m_gpio);
ppd42ns_close(m_ppd42ns);
}
dustData PPD42NS::getData()
ppd42ns_dust_data PPD42NS::getData()
{
dustData data;
struct timespec printData_start={0,0};
struct timespec printData_now={0,0};
clock_gettime(CLOCK_MONOTONIC, &printData_start);
clock_gettime(CLOCK_MONOTONIC, &printData_now);
double low_pulse_occupancy = 0;
double pulse_check_time = 30;
// Keep reading dust data until 30 seconds have passed
double start_time, end_time;
while (m_timediff(printData_start, printData_now) < pulse_check_time)
{
start_time = m_timediff(printData_start, printData_now);
end_time = pulse_check_time - start_time;
low_pulse_occupancy += pulseIn_polyfill(0, end_time);
clock_gettime(CLOCK_MONOTONIC, &printData_now);
}
// Store dust data
double ratio = low_pulse_occupancy / (pulse_check_time * 1000 * 10.0); // Integer percentage 0=>100
double concentration = (1.1 * pow(ratio,3)) - (3.8 * pow(ratio, 2)) + (520 * ratio) + 0.62; // using spec sheet curve
data.lowPulseOccupancy = (int)low_pulse_occupancy;
data.ratio = ratio;
data.concentration = concentration;
return data;
return ppd42ns_get_data(m_ppd42ns);
}
// Mimicking Arduino's pulseIn function
// return how long it takes a pin to go from HIGH to LOW or LOW to HIGH
double PPD42NS::pulseIn_polyfill(bool high_low_value, double end_time)
{
struct timespec pulseIn_start={0,0};
struct timespec pulseIn_now={0,0};
struct timespec pulsetime_start={0,0};
struct timespec pulsetime_end={0,0};
int pin_val = 5; // some non-zero, non-1 number
bool started_timing = false;
bool ended_timing = false;
clock_gettime(CLOCK_MONOTONIC, &pulseIn_start);
// run through this loop until either:
// a) we detect a change in pulse
// b) we've hit 30 seconds
while (!ended_timing && (m_timediff(pulseIn_start, pulseIn_now) < end_time))
{
pin_val = (bool)mraa_gpio_read(m_gpio);
if (pin_val == high_low_value && !started_timing)
{
clock_gettime(CLOCK_MONOTONIC, &pulsetime_start);
started_timing = true;
//std::cout << "Started counting pulse change" << std::endl;
usleep(50);
}
else if (started_timing && pin_val != high_low_value)
{
clock_gettime(CLOCK_MONOTONIC, &pulsetime_end);
ended_timing = true;
//std::cout << "Ended counting pulse change" << (m_timediff(pulseIn_start, pulseIn_now)) << std::endl;
}
else
usleep(50);
clock_gettime(CLOCK_MONOTONIC, &pulseIn_now);
}
double low_pulse_occupancy = 0;
// if we ended due to detecting a pulse change and not due to hitting 30 seconds
if (started_timing && ended_timing)
low_pulse_occupancy = m_timediff(pulsetime_start, pulsetime_end);
//std::cout << "Low pulse occupancy is " << low_pulse_occupancy << " seconds" << std::endl;
return (low_pulse_occupancy * 1000000); // convert to microseconds
}
double PPD42NS::m_timediff(timespec time1, timespec time2)
{
return ((double)time2.tv_sec + 1.0e-9*time2.tv_nsec) -
((double)time1.tv_sec + 1.0e-9*time1.tv_nsec);
}