Steven Swenson / Mbed 2 deprecated tuner

A program to automatically tune a guitar. Written by Justin Reidhead and Steven Swenson

Dependencies:   FFT FrequencyFinder Motor NewTextLCD PinDetect mbed strings

FrequencyFinder/FrequencyFinder.cpp@11:bdad1acccdad, 2012-04-25 (annotated)

Committer:
melangeaddict
Date:
Wed Apr 25 00:42:46 2012 +0000
Revision:
11:bdad1acccdad
Parent:
10:4566e8aeb3ae
Child:
12:03c189de6e2e
messed with gains of the strings;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
melangeaddict 2:9c0a83c5ded5 1 #include "FrequencyFinder.h"
melangeaddict 2:9c0a83c5ded5 2
melangeaddict 2:9c0a83c5ded5 3 using namespace std;
melangeaddict 2:9c0a83c5ded5 4
melangeaddict 9:2a211133e79a 5 FrequencyFinder::FrequencyFinder(PinName input) : _signal_in(input), _dc_offset(p18) {
melangeaddict 2:9c0a83c5ded5 6 index=0;
melangeaddict 2:9c0a83c5ded5 7 peak=0;
melangeaddict 2:9c0a83c5ded5 8 frequency_final=0;
melangeaddict 2:9c0a83c5ded5 9 }
melangeaddict 2:9c0a83c5ded5 10
melangeaddict 2:9c0a83c5ded5 11 FrequencyFinder::~FrequencyFinder() {
melangeaddict 2:9c0a83c5ded5 12 ticker.detach();
melangeaddict 2:9c0a83c5ded5 13 }
melangeaddict 2:9c0a83c5ded5 14
melangeaddict 2:9c0a83c5ded5 15 float FrequencyFinder::find_frequency() {
melangeaddict 2:9c0a83c5ded5 16 initialize_array();
melangeaddict 2:9c0a83c5ded5 17 ticker.attach_us(this, &FrequencyFinder::get_data,500);
melangeaddict 2:9c0a83c5ded5 18
melangeaddict 2:9c0a83c5ded5 19 wait(1);
melangeaddict 2:9c0a83c5ded5 20 ticker.detach();
melangeaddict 2:9c0a83c5ded5 21
melangeaddict 9:2a211133e79a 22 copy_data();
melangeaddict 2:9c0a83c5ded5 23
melangeaddict 10:4566e8aeb3ae 24 vRealFFT(signal_array,size);
melangeaddict 10:4566e8aeb3ae 25
melangeaddict 2:9c0a83c5ded5 26 take_abs();
melangeaddict 2:9c0a83c5ded5 27
melangeaddict 2:9c0a83c5ded5 28 int peak = find_peak();
melangeaddict 2:9c0a83c5ded5 29
melangeaddict 2:9c0a83c5ded5 30 float frequency_final=((float)peak)/4.1;
melangeaddict 2:9c0a83c5ded5 31
melangeaddict 2:9c0a83c5ded5 32 return frequency_final;
melangeaddict 2:9c0a83c5ded5 33 }
melangeaddict 2:9c0a83c5ded5 34
melangeaddict 2:9c0a83c5ded5 35 void FrequencyFinder::get_data() {
melangeaddict 2:9c0a83c5ded5 36 if (index<size) {
melangeaddict 10:4566e8aeb3ae 37 signal_array[index]=_signal_in.read();//-0.5;
melangeaddict 2:9c0a83c5ded5 38 index++;
melangeaddict 2:9c0a83c5ded5 39 }
melangeaddict 2:9c0a83c5ded5 40 }
melangeaddict 2:9c0a83c5ded5 41
melangeaddict 2:9c0a83c5ded5 42 void FrequencyFinder::take_abs() {
melangeaddict 2:9c0a83c5ded5 43 //takes the absolute value of the signal
melangeaddict 2:9c0a83c5ded5 44 for (int j=0; j<size; j++) {
melangeaddict 2:9c0a83c5ded5 45 signal_array[j]=abs(signal_array[j]);
melangeaddict 11:bdad1acccdad 46 if (j<200)//~48Hz
melangeaddict 2:9c0a83c5ded5 47 signal_array[j]=0;
melangeaddict 11:bdad1acccdad 48 else if (j<400)//~97Hz
melangeaddict 8:651fbf5ae98a 49 signal_array[j]=signal_array[j]*5;
melangeaddict 11:bdad1acccdad 50 else if (j<600)//~146Hz
melangeaddict 8:651fbf5ae98a 51 signal_array[j]=signal_array[j]*6;
melangeaddict 11:bdad1acccdad 52 else if (j<900)//~219Hz
melangeaddict 8:651fbf5ae98a 53 signal_array[j]=signal_array[j]*7;
melangeaddict 11:bdad1acccdad 54 else if (j<1200)//292Hz
melangeaddict 11:bdad1acccdad 55 signal_array[j]=signal_array[j]*25;
melangeaddict 2:9c0a83c5ded5 56 else
melangeaddict 11:bdad1acccdad 57 signal_array[j]=signal_array[j]*30;
melangeaddict 2:9c0a83c5ded5 58 }
melangeaddict 2:9c0a83c5ded5 59 }
melangeaddict 2:9c0a83c5ded5 60
melangeaddict 2:9c0a83c5ded5 61 int FrequencyFinder::find_peak() {
melangeaddict 2:9c0a83c5ded5 62 int i=0;
melangeaddict 2:9c0a83c5ded5 63
melangeaddict 2:9c0a83c5ded5 64 for (int j=0; j<size; j++) {
melangeaddict 2:9c0a83c5ded5 65 if ((signal_array[i]-signal_array[i-1])>100 ) {
melangeaddict 2:9c0a83c5ded5 66 while (
melangeaddict 2:9c0a83c5ded5 67 (signal_array[i]<=signal_array[i+1]) &&
melangeaddict 2:9c0a83c5ded5 68 (signal_array[i]<=signal_array[i+2]) &&
melangeaddict 2:9c0a83c5ded5 69 (signal_array[i]<=signal_array[i+3]) &&
melangeaddict 2:9c0a83c5ded5 70 (signal_array[i]<=signal_array[i+4])) {
melangeaddict 2:9c0a83c5ded5 71 i++;
melangeaddict 2:9c0a83c5ded5 72 }
melangeaddict 2:9c0a83c5ded5 73 return FrequencyFinder::find_max(i);
melangeaddict 2:9c0a83c5ded5 74 }
melangeaddict 2:9c0a83c5ded5 75 i++;
melangeaddict 2:9c0a83c5ded5 76 }
melangeaddict 2:9c0a83c5ded5 77 return FrequencyFinder::find_max(i);
melangeaddict 2:9c0a83c5ded5 78 }
melangeaddict 2:9c0a83c5ded5 79
melangeaddict 2:9c0a83c5ded5 80 int FrequencyFinder::find_max(int position) {
melangeaddict 2:9c0a83c5ded5 81 int index1=position-20;
melangeaddict 2:9c0a83c5ded5 82 int index2=position+20;
melangeaddict 2:9c0a83c5ded5 83 float max=signal_array[index1];
melangeaddict 2:9c0a83c5ded5 84 int max_index=0;
melangeaddict 2:9c0a83c5ded5 85
melangeaddict 2:9c0a83c5ded5 86 for (int a=index1; a<index2; a++) {
melangeaddict 2:9c0a83c5ded5 87 if (signal_array[a]>max) {
melangeaddict 2:9c0a83c5ded5 88 max=signal_array[a];
melangeaddict 2:9c0a83c5ded5 89 max_index=a;
melangeaddict 2:9c0a83c5ded5 90 }
melangeaddict 2:9c0a83c5ded5 91 }
melangeaddict 2:9c0a83c5ded5 92
melangeaddict 2:9c0a83c5ded5 93 return max_index;
melangeaddict 2:9c0a83c5ded5 94 }
melangeaddict 2:9c0a83c5ded5 95
melangeaddict 2:9c0a83c5ded5 96 void FrequencyFinder::initialize_array() {
melangeaddict 2:9c0a83c5ded5 97 index=0;
melangeaddict 2:9c0a83c5ded5 98 for (int w=0; w<size; w++) {
melangeaddict 2:9c0a83c5ded5 99 signal_array[w]=0;
melangeaddict 2:9c0a83c5ded5 100 }
melangeaddict 9:2a211133e79a 101 }
melangeaddict 9:2a211133e79a 102
melangeaddict 9:2a211133e79a 103 void FrequencyFinder::copy_data() {
melangeaddict 9:2a211133e79a 104 for (int i=0; i<size/2; i++) {
melangeaddict 9:2a211133e79a 105 signal_array[i+(size/2)]=signal_array[i];
melangeaddict 9:2a211133e79a 106 }
melangeaddict 2:9c0a83c5ded5 107 }