SmoothAnalogIn.h

00001 // SmoothAnalogIn.h: Martyn Stopps / Taneli Holtta : 18-06-10
00002 
00003 // Header file: included by other code so we what is available (the declaration)
00004 
00005 // SmoothAnalogIn class that takes arguments PinName, adc sample rate, smoothing factor and scaling factor
00006 // PinName: P15..20 (analogue inputs)
00007 // adc sampling rate: duration in seconds ie 0.01 = 100Hz (a ticker in the class takes care of sampling)
00008 // smoothing factor: 1 to x (smoothed value +-difference)/x
00009 // scaling factor: adc returns float O to 1 representing 0  to 3.3V) ie a scaling factor of 3300 returns actual adc input in mV 
00010 
00011 // To use the class
00012 // #include "SmoothAnalogIn.h" in main.cpp           // include SmoothAnalogIn header file
00013 // SmoothAnalogIn tc1(p15,0.01,5,3300);              // (PinName, sampleRate, smoothingFactor, adcScaling) 
00014 // SmoothAnalogIn tc2(p16,0.01,500,3300);            // (PinName, sampleRate, smoothingFactor, adcScaling) 
00015 // tc1.read()                                        // return tc1 smoothed adc value
00016 
00017 
00018 #include "mbed.h"                           // tested with revision 23
00019 
00020 class SmoothAnalogIn    {                   // Class
00021 
00022     public:
00023     
00024         SmoothAnalogIn(PinName pin, float sampleRate, int smoothingFactor, int adcScaling);
00025         
00026         double read (void);                 // public- returns smoothed adc value
00027         
00028         
00029     private:
00030     
00031         // private objects
00032         
00033         AnalogIn _adc;                      // AnalogIn
00034         Ticker _ticker;                     // Ticker within class
00035     
00036         // private functions
00037         
00038         void smoothValue(double);           // function to smooth adc value
00039         void sampleAdc(void);               // gets current adc value and then calls smoothing function 'void smoothValue(double);'  
00040        
00041        
00042        // private variables
00043        
00044        double smoothed;                     // smoothed adc value
00045        int _smoothingFactor;                // instance value - smoothing factor
00046        int _adcScaling;                     // instance value -adc scaling factor
00047              
00048                         };