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 #pragma once
25 
26 #include <string>
27 #include <iostream>
28 #include <stdint.h>
29 #include <mraa/aio.h>
30 
31 // reference voltage in millivolts
32 #define GROVEVDIV_VREF  4980
33 
34 // default ADC resolution
35 #define GROVEVDIV_ADC_RES 1024
36 
37 namespace upm {
38   /**
39    * @brief Grove Voltage Divider Sensor library
40    * @defgroup grovevdiv libupm-grovevdiv
41    * @ingroup seeed analog electric robok
42    */
43 
44   /**
45    * @library grovevdiv
46    * @sensor grovevdiv
47    * @comname Grove Voltage Divider
48    * @type electric
49    * @man seeed
50    * @con analog
51    * @kit robok
52    *
53    * @brief API for the Grove Voltage Divider Sensor
54    *
55    * UPM module for the Grove Voltage Divider sensor
56    *
57    * @image html grovevdiv.jpg
58    * @snippet grovevdiv.cxx Interesting
59    */
60   class GroveVDiv {
61   public:
62     /**
63      * Grove Voltage Divider sensor constructor
64      *
65      * @param pin Analog pin to use
66      */
67     GroveVDiv(int pin);
68 
69     /**
70      * Grove Voltage Divider destructor
71      */
72     ~GroveVDiv();
73 
74     /**
75      * Gets the conversion value from the sensor
76      *
77      * @param samples Specifies how many samples to average over
78      * @return Average ADC conversion value
79      */
80     unsigned int value(unsigned int samples);
81 
82     /**
83      * Computes the measured voltage
84      *
85      * @param gain Gain switch, either 3 or 10 for Grove
86      * @param val Measured voltage (from value())
87      * @param vref Reference voltage in millivolts
88      * @param res ADC resolution
89      *
90      * @return Measured voltage
91      */
92     float computedValue(uint8_t gain, unsigned int val, int vref=GROVEVDIV_VREF,
93                         int res=GROVEVDIV_ADC_RES);
94 
95   private:
96     mraa_aio_context m_aio;
97   };
98 }
99