Add FFT Tutorial example

examples/Tutorial/Part_1_03_Playing_Music/Part_1_03_Playing_Music.ino

@@ -1,6 +1,9 @@
 // Advanced Microcontroller-based Audio Workshop
 // 
 // Part 1-3: First "Hello World" program, play a music file
+//
+// WAV files for this and other Tutorials are here:
+// http://www.pjrc.com/teensy/td_libs_AudioDataFiles.html
 
 #include <Audio.h>
 #include <Wire.h>

examples/Tutorial/Part_3_02_Fourier_Transform/AudioSampleGuitar.h

@@ -0,0 +1,3 @@
+// Audio data converted from WAV file by wav2sketch
+
+extern const unsigned int AudioSampleGuitar[36929];

examples/Tutorial/Part_3_02_Fourier_Transform/Part_3_02_Fourier_Transform.ino

@@ -0,0 +1,175 @@
+// Advanced Microcontroller-based Audio Workshop
+// 
+// Part 3-1: Fourier Transform
+
+#include <Bounce.h>
+#include "AudioSampleGuitar.h"
+Bounce button0 = Bounce(0, 15);
+Bounce button1 = Bounce(1, 15);  // 15 = 15 ms debounce time
+Bounce button2 = Bounce(2, 15);
+
+
+///////////////////////////////////
+// copy the Design Tool code here
+///////////////////////////////////
+
+
+
+
+
+void setup() {
+  Serial.begin(9600);
+  AudioMemory(10);
+  sgtl5000_1.enable();
+  sgtl5000_1.volume(0.5);
+  SPI.setMOSI(7);
+  SPI.setSCK(14);
+  if (!(SD.begin(10))) {
+    while (1) {
+      Serial.println("Unable to access the SD card");
+      delay(500);
+    }
+  }
+  pinMode(0, INPUT_PULLUP);
+  pinMode(1, INPUT_PULLUP);
+  pinMode(2, INPUT_PULLUP);
+  mixer1.gain(0, 0.5);
+  mixer1.gain(1, 0.5);
+  mixer1.gain(2, 0.0);
+  mixer1.gain(3, 0.0);
+  // Uncomment one these to try other window functions
+  // fft1024_1.windowFunction(NULL);
+  // fft1024_1.windowFunction(AudioWindowBartlett1024);
+  // fft1024_1.windowFunction(AudioWindowFlattop1024);
+  delay(1000);
+  playSdWav1.play("SDTEST1.WAV");
+
+}
+
+
+int fileNumber = 0;
+const char * filenames[4] = {
+  "SDTEST1.WAV", "SDTEST2.WAV", "SDTEST3.WAV", "SDTEST4.WAV"
+};
+
+int noteNumber = 0;
+const float noteFrequency[12] = {
+  200.00,  // A3
+  233.08,  // A#3
+  246.94,  // B3
+  261.63,  // C4
+  277.18,  // C#4
+  293.66,  // D4
+  311.13,  // D#4
+  329.63,  // E4
+  349.23,  // F4
+  369.99,  // F#4
+  392.00,  // G4
+  415.30   // G#4
+};
+
+
+
+void loop() {
+
+  // print Fourier Transform data to the Arduino Serial Monitor
+  if (fft1024_1.available()) {
+    
+    Serial.print("FFT: ");
+    for (int i=0; i<30; i++) {  // 0-25  -->  DC to 1.25 kHz
+      float n = fft1024_1.read(i);
+      printNumber(n);
+    }
+    Serial.println();
+  }
+  
+  button0.update();
+  button1.update();
+  button2.update();
+
+  // Left button starts playing a new song
+  if (button0.fallingEdge()) {
+    mixer1.gain(2, 0.0);
+    mixer1.gain(3, 0.0);
+    fileNumber = fileNumber + 1;
+    if (fileNumber >= 4) fileNumber = 0;
+    playMem1.stop();
+    playSdWav1.play(filenames[fileNumber]);
+    mixer1.gain(0, 0.5);
+    mixer1.gain(1, 0.5);
+  }
+
+  // Middle button plays Guitar sample
+  if (button1.fallingEdge()) {
+    mixer1.gain(0, 0.0);
+    mixer1.gain(1, 0.0);
+    mixer1.gain(3, 0.0);
+    playSdWav1.stop();
+    playMem1.play(AudioSampleGuitar);
+    mixer1.gain(2, 1.0);
+  }
+
+  // Right button plays a pure sine wave tone
+  if (button2.fallingEdge()) {
+    mixer1.gain(0, 0.0);
+    mixer1.gain(1, 0.0);
+    mixer1.gain(2, 0.0);
+    playSdWav1.stop();
+    playMem1.stop();
+    waveform1.begin(1.0, noteFrequency[noteNumber], WAVEFORM_SINE);
+    noteNumber = noteNumber + 1;
+    if (noteNumber >= 12) noteNumber = 0;
+    mixer1.gain(3, 1.0);
+  }
+  if (button2.risingEdge()) {
+    waveform1.amplitude(0);
+  }
+/*
+  if (fft1024_1.available()) {
+    // each time new FFT data is available
+    // print to the Arduino Serial Monitor
+    Serial.print("FFT: ");
+    printNumber(fft1024_1.read(0));
+    printNumber(fft1024_1.read(1));
+    printNumber(fft1024_1.read(2,3));
+    printNumber(fft1024_1.read(4,6));
+    printNumber(fft1024_1.read(7,10));
+    printNumber(fft1024_1.read(11,15));
+    printNumber(fft1024_1.read(16,22));
+    printNumber(fft1024_1.read(23,32));
+    printNumber(fft1024_1.read(33,46));
+    printNumber(fft1024_1.read(47,66));
+    printNumber(fft1024_1.read(67,93));
+    printNumber(fft1024_1.read(94,131));
+    printNumber(fft1024_1.read(132,184));
+    printNumber(fft1024_1.read(185,257));
+    printNumber(fft1024_1.read(258,359));
+    printNumber(fft1024_1.read(360,511));
+    Serial.println();
+  }
+*/
+
+}
+
+
+void printNumber(float n) {
+  
+  if (n >= 0.004) {
+    Serial.print(n, 3);
+    Serial.print(" ");
+  } else {
+    Serial.print("   -  "); // don't print "0.00"
+  }
+  
+  /*
+  if (n > 0.25) {
+    Serial.print("***** ");
+  } else if (n > 0.18) {
+    Serial.print(" ***  ");
+  } else if (n > 0.06) {
+    Serial.print("  *   ");
+  } else if (n > 0.005) {
+    Serial.print("  .   ");
+  }
+  */
+}