1 /*
2  * Author: Brendan Le Foll <brendan.le.foll@intel.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 #pragma once
25 
26 #include <string>
27 #include <mraa/aio.hpp>
28 
29 struct thresholdContext {
30     long averageReading;
31     long runningAverage;
32     int averagedOver;
33 };
34 
35 namespace upm {
36 /**
37  * @brief Gas Sensor library
38  *
39  * Library for air quality and gas detecting sensors. Base class Gas provides buffered
40  * sampling, threshold checking, basic printing function, and standard read function.
41  *
42  * @defgroup gas libupm-gas
43  * @ingroup seeed analog gaseous eak hak
44  */
45 class Gas {
46     public:
47         /**
48          * Instantiates a Gas object
49          *
50          * @param gasPin Pin where gas is connected
51          */
52         Gas(int gasPin);
53 
54         /**
55          * Gas object destructor
56          */
57         ~Gas();
58 
59         /**
60          * Gets samples from the gas sensor according to the provided window and
61          * number of samples
62          *
63          * @param freqMS Time between each sample (in milliseconds)
64          * @param numberOfSamples Number of sample to sample for this window
65          * @param buffer Buffer with sampled data
66          */
67         virtual int getSampledWindow (unsigned int freqMS, int numberOfSamples, uint16_t * buffer);
68 
69         /**
70          * Given the sampled buffer, this method returns TRUE/FALSE if the threshold
71          * is reached
72          *
73          * @param ctx Threshold context
74          * @param threshold Sample threshold
75          * @param buffer Buffer with samples
76          * @param len Buffer length
77          */
78         virtual int findThreshold (thresholdContext* ctx, unsigned int threshold, uint16_t * buffer, int len);
79 
80         /**
81          * Returns average data for the sampled window
82          *
83          * @param ctx Threshold context
84          */
85         virtual int getSampledData (thresholdContext* ctx);
86 
87         /**
88          * Returns one sample from the sensor
89          */
90         virtual int getSample ();
91 
92         /**
93          *
94          * Prints a running average of the threshold context
95          *
96          * @param ctx Threshold context
97          */
98         virtual void printGraph (thresholdContext* ctx, uint8_t resolution);
99 
100     protected:
101         mraa::Aio    m_aio;
102 };
103 
104 }
105