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      1 /*
      2  * Author: Jon Trulson <jtrulson (at) 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