1 /*
2 * Author: Jon Trulson <jtrulson@ics.com>
3 * Copyright (c) 2015 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 "gp2y0a.h"
30
31 using namespace std;
32 using namespace upm;
33
GP2Y0A(int pin)34 GP2Y0A::GP2Y0A(int pin)
35 {
36 if (!(m_aio = mraa_aio_init(pin)))
37 {
38 throw std::invalid_argument(std::string(__FUNCTION__) +
39 ": mraa_aio_init() failed, invalid pin?");
40 return;
41 }
42
43 // get the ADC resolution
44 m_aRes = (1 << mraa_aio_get_bit(m_aio));
45 }
46
~GP2Y0A()47 GP2Y0A::~GP2Y0A()
48 {
49 mraa_aio_close(m_aio);
50 }
51
value(float aref,uint8_t samples)52 float GP2Y0A::value(float aref, uint8_t samples)
53 {
54 int val;
55 int sum = 0;
56
57 for (int i=0; i<samples; i++)
58 {
59 val = mraa_aio_read(m_aio);
60 sum += val;
61 }
62
63 val = sum / samples;
64 float volts = float(val) * aref / float(m_aRes);
65
66 return volts;
67 }
68