Mike Pollock
Adapted code from original GT_Tuner code (by Andrew Durand) for a school project by Tapton School.
Diff: main.cpp
- Revision:
- 0:6b0b61d411ad
- Child:
- 1:c8ec50d75f80
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Tue Jan 03 13:46:19 2017 +0000
@@ -0,0 +1,314 @@
+// Guitar Tuner and Chord Learning Tool using Goertzel's Algorithm //
+// Based on original code created by: Andrew Durand //
+// Adjusted and modified by Tapton School EDS Project Team //
+
+#include "TextLCD.h"
+#include "mbed.h"
+#include "adc.h"
+#include <math.h>
+#define PI 3.1415
+#define SAMPLE_RATE 24000
+
+DigitalOut led_low(LED1);
+DigitalOut led_ok(LED2);
+DigitalOut led_high(LED4);
+InterruptIn button1(p6); //mosi
+DigitalIn myInputPin (p21); //select tuner or chord learning mode
+
+//LCD and Other Random Variables
+//NokiaLCD lcd(p5, p7, p8, p9, NokiaLCD::LCD6610); // mosi, sclk, cs, rst, type
+
+/* This code uses libraries created for 4-bit LCD's based on the HD44780. This
+program was designed for a similar product (Winstar's WH1602B 2x16 LC) working
+into an Mbed LPC1768.
+LCD pins: Pin 1(VSS) to Mbed Gnd, Pin 2(VDD) to Mbed 5v USB output, Pin 3(Vo- contrast)
+to Mbed Gnd (via a 4k7 resistor), Pin 5(R/W) to Mbed Gnd, Pin 15(A)to Mbed 5v USB output, Pin 16(B) to
+MBed Gnd, Pins 4(RS),20(E) and the 4 data bits (DB4 [11] through to DB7 [14])
+go to the Mbed pins described below: */
+
+TextLCD lcd(p10, p12, p15, p16, p29, p30); // rs, e, d4-d7
+
+int string_select = 0;
+int chord_select = 0;
+float high, high1, in_tune, in_tune1, in_tune2, in_tune3,
+low, low1, note, low_mod, high_mod;
+char* key;
+int Counter = 0;
+int Buffer[6000];
+
+float goertzelFilter(int samples[], float freq, int N) {
+ float s_prev = 0.0;
+ float s_prev2 = 0.0;
+ float coeff,normalizedfreq,power,s;
+ int i;
+ normalizedfreq = freq / SAMPLE_RATE;
+ coeff = 2*cos(2*PI*normalizedfreq);
+ for (i=0; i<N; i++) {
+ s = samples[i] + coeff * s_prev - s_prev2;
+ s_prev2 = s_prev;
+ s_prev = s;
+ }
+ power = s_prev2*s_prev2+s_prev*s_prev-coeff*s_prev*s_prev2;
+ return power;
+}
+
+ADC adc(SAMPLE_RATE, 1);
+
+void sample_audio(int chan, uint32_t value) {
+ Buffer[Counter] = adc.read(p20);
+ Counter += 1;
+}
+
+void button1_pressed() {
+ string_select++;
+ chord_select++;
+ if (string_select > 5) string_select = 0;
+ if (chord_select > 9) chord_select = 0;//change for number of chords supported
+}
+
+int main() {
+ while (1) {
+ myInputPin.mode(PullUp); //set the mbed to use a pullup resistor
+ if (myInputPin) { //select guitar tuner or chord teaching
+ lcd.cls (); // Guitar Tuner Section based on p21 being +3v
+
+ //Interupt for Switching Strings
+ button1.mode(PullDown);
+ button1.rise(&button1_pressed);
+
+ while (1) {
+
+ switch (string_select) {
+ case 0:
+ note = 82;
+ key= "E2";
+ break;
+ case 1:
+ note = 110;
+ key= "A2";
+ break;
+ case 2:
+ note = 147;
+ key= "D3";
+ break;
+ case 3:
+ note = 196;
+ key= "G3";
+ break;
+ case 4:
+ note = 247;
+ key= "B3";
+ break;
+ case 5:
+ note = 330;
+ key= "E4";
+ break;
+ }
+
+ //Prepare for burst mode on all ADC pins and set up interrupt handler (using ADC library from Simon Blandford
+ adc.append(sample_audio);
+ adc.startmode(0,0);
+ adc.burst(1);
+ adc.setup(p20,1);
+
+ //start the interrupt and wait for about 4096 samples
+ adc.interrupt_state(p20,1);
+ wait(.2);
+
+ //Finsh up - Unset pin 20
+ adc.interrupt_state(p20,0);
+ adc.setup(p20,0);
+ int actual_rate = adc.actual_sample_rate();
+
+ //for debugging tell the terminal sample rate and how many samples we took
+ printf("Requested max sample rate is %u, actual max sample rate is %u.\n",
+ SAMPLE_RATE, actual_rate);
+ printf("We did %i samples\n",Counter);
+
+ high = 0;
+ low = 0;
+ for (int i=3; i<46; i+=3) {
+ high1 = goertzelFilter(Buffer, (note + i ), Counter);
+ if (high1 > high) high=high1;
+ }
+ for (int i=3; i<46; i+=3) {
+ low1 = goertzelFilter(Buffer, (note - i ), Counter);
+ if (low1 > low) low=low1;
+ }
+ in_tune1 = goertzelFilter(Buffer, (note+1), Counter);
+ in_tune2 = goertzelFilter(Buffer, note, Counter);
+ in_tune3 = goertzelFilter(Buffer, (note-1), Counter);
+
+ if ((in_tune1 > in_tune2) && (in_tune1 > in_tune3)) in_tune = in_tune1;
+ else if ((in_tune2 > in_tune1) && (in_tune2 > in_tune3)) in_tune = in_tune2;
+ else in_tune = in_tune3;
+
+ if ((in_tune > high) && (in_tune > low)) {
+ led_high = 0;
+ led_ok = 1;
+ led_low = 0;
+ } else if (high > in_tune) {
+ led_high = 1;
+ led_ok = 0;
+ led_low = 0;
+ } else if (low > in_tune) {
+ led_high = 0;
+ led_ok = 0;
+ led_low = 1;
+ } else {
+ led_high = 0;
+ led_ok = 0;
+ led_low = 0;
+ }
+
+ int pintwenty = adc.read(p20); //read pin 20
+ lcd.locate(0,1);
+ lcd.printf("%s %iHz %d\n",key, (int) note, pintwenty);
+ if (led_ok) lcd.printf("Tuner- In Tune");
+ else if (led_low) lcd.printf("Tuner- 2Low ");
+ else if (led_high) lcd.printf("Tuner- 2High ");
+ else lcd.printf("~~~~~~~~");
+
+ Counter = 0;
+ } //inner while (1)loop
+ } else { //if myinputpin
+
+ lcd.cls (); //Chord Tutor Section based on p21 being 0v
+
+ //Interupt for Switching chord selection
+ button1.mode(PullDown);
+ button1.rise(&button1_pressed);
+
+
+
+ while (1) {
+
+ switch (chord_select) {
+ case 0:
+ note = 82;
+ key= "E2";
+ //send E chord white LED pattern
+ break;
+ case 1:
+ note = 110;
+ key= "A2";
+ //send A chord white LED pattern
+ break;
+ case 2:
+ note = 147;
+ key= "D3";
+ //send D chord white LED pattern
+ break;
+ case 3:
+ note = 196;
+ key= "G3";
+ //send G chord white LED pattern
+ break;
+ case 4:
+ note = 247;
+ key= "B3";
+ //send B chord white LED pattern
+ break;
+ case 5:
+ note = 2349;
+ key= "D7";
+ //send D7 chord white LED pattern
+ break;
+ case 6:
+ note = 131;
+ key= "C3";
+ //send C chord white LED pattern
+ break;
+ case 7:
+ note = 174;
+ key= "F3";
+ //send F chord white LED pattern
+ break;
+ case 8:
+ note = 65;
+ key= "C2";
+ //send C chord white LED pattern
+ break;
+ case 9:
+ note = 87;
+ key= "F2";
+ //send F chord white LED pattern
+ break;
+ }
+
+ //Prepare for burst mode on all ADC pins and set up interrupt handler (using ADC library from Simon Blandford
+ adc.append(sample_audio);
+ adc.startmode(0,0);
+ adc.burst(1);
+ adc.setup(p20,1);
+
+ //start the interrupt and wait for about 4096 samples
+ adc.interrupt_state(p20,1);
+ wait(.2);
+
+ //Finsh up - Unset pin 20
+ adc.interrupt_state(p20,0);
+ adc.setup(p20,0);
+ int actual_rate = adc.actual_sample_rate();
+
+ //for debugging tell the terminal sample rate and how many samples we took
+ printf("Requested max sample rate is %u, actual max sample rate is %u.\n",
+ SAMPLE_RATE, actual_rate);
+ printf("We did %i samples\n",Counter);
+
+high = 0;
+low = 0;
+for (int i=3; i<46; i+=3) {
+ high1 = goertzelFilter(Buffer, (note + i ), Counter);
+ if (high1 > high) high=high1;
+}
+for (int i=3; i<46; i+=3) {
+ low1 = goertzelFilter(Buffer, (note - i ), Counter);
+ if (low1 > low) low=low1;
+}
+ in_tune1 = goertzelFilter(Buffer, (note+1), Counter);
+ in_tune2 = goertzelFilter(Buffer, note, Counter);
+ in_tune3 = goertzelFilter(Buffer, (note-1), Counter);
+
+ if ((in_tune1 > in_tune2) && (in_tune1 > in_tune3)) in_tune = in_tune1;
+ else if ((in_tune2 > in_tune1) && (in_tune2 > in_tune3)) in_tune = in_tune2;
+ else in_tune = in_tune3;
+ if ((in_tune > high) && (in_tune > low)) {
+ led_high = 0;
+ led_ok = 1;
+ led_low = 0;
+ } else if (high > in_tune) {
+ led_high = 1;
+ led_ok = 0;
+ led_low = 0;
+ } else if (low > in_tune) {
+ led_high = 0;
+ led_ok = 0;
+ led_low = 1;
+ } else {
+ led_high = 0;
+ led_ok = 0;
+ led_low = 0;
+ }
+
+ int pintwenty = adc.read(p20); //read pin 20
+ lcd.locate(0,1);
+ lcd.printf("%s ",key);
+ lcd.locate(4,1);// need to deal with lcd screen changes to length of frequencies
+ lcd.printf(" ");
+ lcd.locate(4,1);
+ lcd.printf("%iHz",(int) note);
+ lcd.locate(11,1);
+ lcd.printf("%4d\n",pintwenty); //need to deal with lcd screen changes to restrict input decimal range to 4sf
+ if (led_ok) lcd.printf("Play %s->In Tune",key); //if statement here for send green LED pattern for selected chord
+ else if (led_low) lcd.printf("Play %s -> 2Low ",key);//if statement here for send red LED pattern for selected chord
+ else if (led_high) lcd.printf("Play %s -> 2High",key);//if statement here for send red LED pattern for selected chord
+ else lcd.printf("~~~~~~~~");
+
+ Counter = 0;
+ }
+ }
+
+
+ }
+}
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