teensy-audio/examples/Effects/Granular/Granular.ino

// Granular Effect Example - Pitch shift or freeze sound
//
// This example is meant to be used with 3 buttons (pin 0,
// 1, 2) and 2 knobs (pins 16/A2, 17/A3), which are present
// on the audio tutorial kit.
//   https://www.pjrc.com/store/audio_tutorial_kit.html
//
// Data files to put on your SD card can be downloaded here:
//   http://www.pjrc.com/teensy/td_libs_AudioDataFiles.html
//
// This example code is in the public domain.

#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>
#include <Bounce.h>

AudioPlaySdWav           playSdWav1;     //xy=163,135
AudioMixer4              mixer1;         //xy=332,167
AudioEffectGranular      granular1;      //xy=504,155
AudioOutputI2S           i2s1;           //xy=664,185
AudioConnection          patchCord1(playSdWav1, 0, mixer1, 0);
AudioConnection          patchCord2(playSdWav1, 1, mixer1, 1);
AudioConnection          patchCord3(mixer1, granular1);
AudioConnection          patchCord4(granular1, 0, i2s1, 0);
AudioConnection          patchCord5(granular1, 0, i2s1, 1);
AudioControlSGTL5000     sgtl5000_1;     //xy=236,248

Bounce button0 = Bounce(0, 15);
Bounce button1 = Bounce(1, 15);
Bounce button2 = Bounce(2, 15);

#define GRANULAR_MEMORY_SIZE 12800  // enough for 290 ms at 44.1 kHz
int16_t granularMemory[GRANULAR_MEMORY_SIZE];

// Use these with the Teensy Audio Shield
#define SDCARD_CS_PIN    10
#define SDCARD_MOSI_PIN  7
#define SDCARD_SCK_PIN   14

// Use these with the Teensy 3.5 & 3.6 SD card
//#define SDCARD_CS_PIN    BUILTIN_SDCARD
//#define SDCARD_MOSI_PIN  11  // not actually used
//#define SDCARD_SCK_PIN   13  // not actually used

// Use these for the SD+Wiz820 or other adaptors
//#define SDCARD_CS_PIN    4
//#define SDCARD_MOSI_PIN  11
//#define SDCARD_SCK_PIN   13

#define NUM_FILES  4
const char *filenames[NUM_FILES]={"SDTEST1.WAV", "SDTEST2.WAV", "SDTEST3.WAV", "SDTEST4.WAV"};
int nextfile=0;

void setup() {
  Serial.begin(9600);
  AudioMemory(10);

  pinMode(0, INPUT_PULLUP);
  pinMode(1, INPUT_PULLUP);
  pinMode(2, INPUT_PULLUP);

  sgtl5000_1.enable();
  sgtl5000_1.volume(0.5);

  mixer1.gain(0, 0.5);
  mixer1.gain(1, 0.5);

  // the Granular effect requires memory to operate
  granular1.begin(granularMemory, GRANULAR_MEMORY_SIZE);

  SPI.setMOSI(SDCARD_MOSI_PIN);
  SPI.setSCK(SDCARD_SCK_PIN);
  if (!(SD.begin(SDCARD_CS_PIN))) {
    // stop here, but print a message repetitively
    while (1) {
      Serial.println("Unable to access the SD card");
      delay(500);
    }
  }
}

void loop() {
  if (playSdWav1.isPlaying() == false) {
    // start the next song playing
    playSdWav1.play(filenames[nextfile]);
    Serial.print("Playing: ");
    Serial.println(filenames[nextfile]);
    delay(5); // brief delay for the library read WAV info
    nextfile = nextfile + 1;
    if (nextfile >= NUM_FILES) {
      nextfile = 0;
    }
  }

  // read pushbuttons
  button0.update();
  button1.update();
  button2.update();
  // read knobs, scale to 0-1.0 numbers
  float knobA2 = (float)analogRead(A2) / 1023.0;
  float knobA3 = (float)analogRead(A3) / 1023.0;

  // Button 0 starts Freeze effect
  if (button0.fallingEdge()) {
    float msec = 100.0 + (knobA3 * 190.0);
    granular1.beginFreeze(msec);
    Serial.print("Begin granular freeze using ");
    Serial.print(msec);
    Serial.println(" grains");
  }
  if (button0.risingEdge()) {
    granular1.stop();
  }

  // Button 1 starts Pitch Shift effect
  if (button1.fallingEdge()) {
    float msec = 25.0 + (knobA3 * 75.0);
    granular1.beginPitchShift(msec);
    Serial.print("Begin granular pitch phift using ");
    Serial.print(msec);
    Serial.println(" grains");
  }
  if (button1.risingEdge()) {
    granular1.stop();
  }

  // Continuously adjust the speed, based on the A3 pot
  float ratio;
  ratio = powf(2.0, knobA2 * 2.0 - 1.0); // 0.5 to 2.0
  //ratio = powf(2.0, knobA2 * 6.0 - 3.0); // 0.125 to 8.0 -- uncomment for far too much range!
  granular1.setSpeed(ratio);
}