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@10:4566e8aeb3ae, 2012-04-24 (annotated)

Committer:
melangeaddict
Date:
Tue Apr 24 23:20:53 2012 +0000
Revision:
10:4566e8aeb3ae
Parent:
9:2a211133e79a
Child:
11:bdad1acccdad
It worksss!!...kinda; Really slow, but works

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 2:9c0a83c5ded5 46 if (j<100)
melangeaddict 2:9c0a83c5ded5 47 signal_array[j]=0;
melangeaddict 2:9c0a83c5ded5 48 else if (j<400)
melangeaddict 8:651fbf5ae98a 49 signal_array[j]=signal_array[j]*5;
melangeaddict 2:9c0a83c5ded5 50 else if (j<600)
melangeaddict 8:651fbf5ae98a 51 signal_array[j]=signal_array[j]*6;
melangeaddict 2:9c0a83c5ded5 52 else if (j<800)
melangeaddict 8:651fbf5ae98a 53 signal_array[j]=signal_array[j]*7;
melangeaddict 2:9c0a83c5ded5 54 else
melangeaddict 10:4566e8aeb3ae 55 signal_array[j]=signal_array[j]*10;
melangeaddict 2:9c0a83c5ded5 56 }
melangeaddict 2:9c0a83c5ded5 57 }
melangeaddict 2:9c0a83c5ded5 58
melangeaddict 2:9c0a83c5ded5 59 int FrequencyFinder::find_peak() {
melangeaddict 2:9c0a83c5ded5 60 int i=0;
melangeaddict 2:9c0a83c5ded5 61
melangeaddict 2:9c0a83c5ded5 62 for (int j=0; j<size; j++) {
melangeaddict 2:9c0a83c5ded5 63 if ((signal_array[i]-signal_array[i-1])>100 ) {
melangeaddict 2:9c0a83c5ded5 64 while (
melangeaddict 2:9c0a83c5ded5 65 (signal_array[i]<=signal_array[i+1]) &&
melangeaddict 2:9c0a83c5ded5 66 (signal_array[i]<=signal_array[i+2]) &&
melangeaddict 2:9c0a83c5ded5 67 (signal_array[i]<=signal_array[i+3]) &&
melangeaddict 2:9c0a83c5ded5 68 (signal_array[i]<=signal_array[i+4])) {
melangeaddict 2:9c0a83c5ded5 69 i++;
melangeaddict 2:9c0a83c5ded5 70 }
melangeaddict 2:9c0a83c5ded5 71 return FrequencyFinder::find_max(i);
melangeaddict 2:9c0a83c5ded5 72 }
melangeaddict 2:9c0a83c5ded5 73 i++;
melangeaddict 2:9c0a83c5ded5 74 }
melangeaddict 2:9c0a83c5ded5 75 return FrequencyFinder::find_max(i);
melangeaddict 2:9c0a83c5ded5 76 }
melangeaddict 2:9c0a83c5ded5 77
melangeaddict 2:9c0a83c5ded5 78 int FrequencyFinder::find_max(int position) {
melangeaddict 2:9c0a83c5ded5 79 int index1=position-20;
melangeaddict 2:9c0a83c5ded5 80 int index2=position+20;
melangeaddict 2:9c0a83c5ded5 81 float max=signal_array[index1];
melangeaddict 2:9c0a83c5ded5 82 int max_index=0;
melangeaddict 2:9c0a83c5ded5 83
melangeaddict 2:9c0a83c5ded5 84 for (int a=index1; a<index2; a++) {
melangeaddict 2:9c0a83c5ded5 85 if (signal_array[a]>max) {
melangeaddict 2:9c0a83c5ded5 86 max=signal_array[a];
melangeaddict 2:9c0a83c5ded5 87 max_index=a;
melangeaddict 2:9c0a83c5ded5 88 }
melangeaddict 2:9c0a83c5ded5 89 }
melangeaddict 2:9c0a83c5ded5 90
melangeaddict 2:9c0a83c5ded5 91 return max_index;
melangeaddict 2:9c0a83c5ded5 92 }
melangeaddict 2:9c0a83c5ded5 93
melangeaddict 2:9c0a83c5ded5 94 void FrequencyFinder::initialize_array() {
melangeaddict 2:9c0a83c5ded5 95 index=0;
melangeaddict 2:9c0a83c5ded5 96 for (int w=0; w<size; w++) {
melangeaddict 2:9c0a83c5ded5 97 signal_array[w]=0;
melangeaddict 2:9c0a83c5ded5 98 }
melangeaddict 9:2a211133e79a 99 }
melangeaddict 9:2a211133e79a 100
melangeaddict 9:2a211133e79a 101 void FrequencyFinder::copy_data() {
melangeaddict 9:2a211133e79a 102 for (int i=0; i<size/2; i++) {
melangeaddict 9:2a211133e79a 103 signal_array[i+(size/2)]=signal_array[i];
melangeaddict 9:2a211133e79a 104 }
melangeaddict 2:9c0a83c5ded5 105 }