main.cpp

#include "mbed.h"
#include "MAX4466.h"
#include "FFT.h"
#include "rtos.h"
#include "uLCD_4DGL.h"
#include "PinDetect.h"
#include <string>
#include <math.h>

PinDetect pb1(p6);
PinDetect pb2(p7);
PinDetect pb3(p8);
PinDetect pb4(p9);
DigitalIn pb5 (p10);
MAX4466 mic(p15);
PwmOut speaker(p21);
uLCD_4DGL uLCD(p28,p27,p30);
Timer tim;

#define MAX_NOTE 11
#define MAX_OCT 8
std::string notes[] = {"C","C#/Db","D","D#/Eb","E","F","F#/Gb","G","G#/Ab","A","A#/Bb","B"};
float notefreqs[] = {16.35,17.32,18.35,19.45,20.60,21.93,23.12,24.50,25.96,27.50,29.14,30.87};

volatile float readfreq = 0.00;
volatile int octave = 0;
volatile int indx = 0;

void pb1_note_down(void) {
    if(!pb1) {
        indx -= 1;
        if (indx < 0) {
            indx = MAX_NOTE; 
        }
    }
}

void pb2_note_up (void) {
    if(!pb2) {
        indx += 1;
        if (indx > MAX_NOTE) {
            indx = 0; 
        }
    }
}

void pb3_oct_down (void) {
   if(!pb3) {
        octave -= 1;
        if (octave < 0) {
            octave = MAX_OCT; 
        }
    }
}

void pb4_oct_up (void) {
   if(!pb4) {
        octave += 1;
        if (octave > MAX_OCT) {
            octave = 0; 
        }
    }
}
//Plays speaker at desired frequency selected by user
void playspeaker(void const *arguments) {
   while (1) {
        speaker.period(1.0/(notefreqs[indx] * pow(2.0f,octave)));
        speaker = 0.0;
        while(!pb5) {
            speaker = 0.5;
        }
        speaker = 0.0;
        Thread::wait(100);
    }
}
//Print frequencies of notes, detected freq, and circle display graphic to LCD
void ulcd(void const *arguments) {
    int cx;
    int old_i = 0;
    int old_oct= 0;
    int i;
    int oct;
    while(1) {
        i = indx;
        oct = octave;
        if (old_oct != oct) {
            old_oct = oct;
            uLCD.locate(1,7);
            uLCD.printf("           ");
        }
        if (old_i != i) {
            old_i = i;
            uLCD.locate(1,7);
            uLCD.printf("           ");
            uLCD.locate(1,3);
            uLCD.printf("           ");
        }
        uLCD.locate(1,3);
        uLCD.printf("%s%D", notes[i], oct);
        uLCD.locate(1,7);
        uLCD.printf("%.2f Hz.", notefreqs[i] * pow(2.0f,oct));
        uLCD.locate(1,14);
        uLCD.printf("%.2f Hz.", readfreq);
        uLCD.filled_circle(108, cx, 5, BLACK);
        if (readfreq <= (notefreqs[i] * pow(2.0f,oct))+ 5 && readfreq >= (notefreqs[i] * pow(2.0f,oct)) - 5) {
            cx = 64;
            uLCD.line(88, 64, 128, 64, GREEN);
            uLCD.filled_circle(108, cx, 5, GREEN);
        } else {
            cx = 64 + (notefreqs[i] * pow(2.0f,oct)) - readfreq;
            if (cx < 0) {
                cx = 0; 
            } else if (cx > 128) {
                cx = 128;    
            }
            uLCD.line(88, 64, 128, 64, RED);
            uLCD.filled_circle(108, cx, 5, RED);
        }
        Thread::wait(10);
    }
}

int main() {
    //set up pindetect
    pb1.mode(PullUp);
    pb2.mode(PullUp);
    pb3.mode(PullUp);
    pb4.mode(PullUp);
    pb5.mode(PullUp);
    wait(0.01);
    pb1.attach_deasserted(&pb1_note_down);
    pb2.attach_deasserted(&pb2_note_up);
    pb3.attach_deasserted(&pb3_oct_down);
    pb4.attach_deasserted(&pb4_oct_up);
    pb1.setSampleFrequency();
    pb2.setSampleFrequency();
    pb3.setSampleFrequency();
    pb4.setSampleFrequency();
    //set intial lcd values
    uLCD.background_color(BLACK);
    uLCD.baudrate(3000000);
    uLCD.line(88, 0, 88, 128, WHITE);
    uLCD.color(WHITE);
    uLCD.locate(1,1);
    uLCD.printf("Note:");
    uLCD.locate(1,5);
    uLCD.printf("Note Freq:");
    uLCD.locate(1,12);
    uLCD.printf("Read Freq:");
    //launch threads
    Thread ulcd_thread(&ulcd);
    Thread speaker_thread(&playspeaker);
    //set up main thread
    int samples = 1024;
    float arr [samples+1];
    arr[0] = 0;
    float max = 0;
    float loc = 0;
    float freq;
    osThreadSetPriority(osThreadGetId(), osPriorityHigh);
    //Loop and constantly be finding frequency of signal
    while (1) { 
        tim.reset();
        tim.start();
        for (int i = 1; i<=samples; i++){
            arr[i] = mic.instantlevel(); //Sample microphone at ~4 Khz
            wait(.00025);
            }
        tim.stop();
        freq = samples/tim.read(); 
        //Turn sampled array into its fourier transform
        vRealFFT(arr,samples); 
        
        //Loop through and find most apparent frequency of sampled signal 
        for(int i = 2; i<=samples; i++){ 
            arr[i] *= arr[i];
            if(max<arr[i]){
                loc = freq/samples * i/2; //determine frequency by using sample rate,index in array
                max = arr[i];
                }
            }
        readfreq = loc; 
        max=0;
        wait(0.25);
        Thread::wait(100);
    }  
}