MAX4466.cpp

00001 #include "mbed.h"
00002 #include "MAX4466.h"
00003 
00004 MAX4466::MAX4466(PinName pin): _pin(pin), _led1(LED1), _led2(LED2), _led3(LED3), _led4(LED4) {
00005     calibration();
00006 }
00007 
00008 //CALIBRATION FUNCTION:
00009 //Find average sound level at the intialization of the microphone
00010 //Use this in the calculation of the LED indication array values
00011 float MAX4466::calibration() {
00012     
00013     _t.start();
00014     _t1.start();
00015     float peakToPeak=0, signalMax=0, signalMin=1024;
00016 
00017     while (_t1.read()<1) {
00018         while (_t.read_ms()<50) {
00019             _sample=_pin.read();
00020 
00021             if (_sample<1024) {
00022                 if (_sample>signalMax)
00023                     signalMax=_sample;
00024 
00025                 else if (_sample<signalMin)
00026                     signalMin=_sample;
00027             }
00028         }
00029      _t.reset();
00030      peakToPeak=signalMax-signalMin;
00031      _value= (peakToPeak*3.3);
00032      _value = floor(_value * 100) / 100;
00033      _sum+=_value;
00034      _count++;
00035     }
00036     _average=_sum/_count;
00037     _t1.reset();
00038 
00039     return _average;
00040 }
00041 
00042 //LED ARRAY FUNCTION:
00043 //Setup array of 4 LEDs 
00044 //The input to this function is the average from the calibration function
00045 //The variable _value which indicates the current value from the microphone is a global variable updated in the sound_level function
00046 //As different threshholds of volume are met more LEDs will light up
00047 void MAX4466::led_array(float x ) {
00048 
00049     if (_value<x+0.05) {
00050             _led1=0;
00051             _led2=0;
00052             _led3=0;
00053             _led4=0;
00054     }
00055     if (_value>x+0.05&&_value<0.5+x) {
00056             _led1=1;
00057             _led2=0;
00058             _led3=0;
00059             _led4=0;
00060     }
00061     if (_value>0.5+x&&_value<1+x) {
00062             _led1=1;
00063             _led2=1;
00064             _led3=0;
00065             _led4=0;
00066     }
00067     if (_value>1+x&&_value<1.2+x) {
00068             _led1=1;
00069             _led2=1;
00070             _led3=1;
00071             _led4=0;
00072     }
00073     if (_value>1.2+x&&_value<2.8+x) {
00074             _led1=1;
00075             _led2=1;
00076             _led3=1;
00077             _led4=1;
00078     }
00079 }
00080 
00081 //SOUND LEVEL FUNCTIOM:
00082 //Read in current sound level from the microphone
00083 //Update the global variable _value which will in turn be read by the LED array function
00084 float MAX4466::sound_level() {
00085 
00086     _t.start();
00087     float peakToPeak=0, signalMax=0, signalMin=1024;
00088 
00089     while (_t.read_ms()<50) {
00090         _sample=_pin.read();
00091 
00092         if (_sample<1024) {
00093             if (_sample>signalMax)
00094                 signalMax=_sample;
00095 
00096             else if (_sample<signalMin)
00097                 signalMin=_sample;
00098         }
00099     }
00100     _t.reset();
00101     peakToPeak=signalMax-signalMin;
00102     _value= (peakToPeak*3.3);
00103     _value = floor(_value * 100) / 100;
00104     _sum+=_value;
00105     _count++;
00106 
00107     return _value;
00108 }
00109 
00110 //VOLUME INDICATOR FUNCTION:
00111 //To be called in main function
00112 //Updates the led array
00113 //outputs current numerical value
00114 void MAX4466::volume_indicator() {
00115         led_array(_average);
00116         sound_level();
00117 }