Update tutorial examples

examples/Tutorial/Part_1_04_Blink_While_Playing/Part_1_04_Blink_While_Playing.ino

     playSdWav1.play("SDTEST3.WAV");
     delay(10); // wait for library to parse WAV info
   }
-  // blink LED and print info while playing
-  digitalWrite(13, HIGH);
+
+  // print the play time offset
   Serial.print("Playing, now at ");
   Serial.print(playSdWav1.positionMillis());
   Serial.println(" ms");
+
+  // blink LED and print info while playing
+  digitalWrite(13, HIGH);
   delay(250);
   digitalWrite(13, LOW);
   delay(250);
+
+  // read the knob position (analog input A2)
+  /*
+  int knob = analogRead(A2);
+  float vol = (float)knob / 1280.0;
+  sgtl5000_1.volume(vol);
+  Serial.print("volume = ");
+  Serial.println(vol);
+  */
 }
 
 

examples/Tutorial/Part_1_05_Do_More_While_Playing/Part_1_05_Do_More_While_Playing.ino

+// Advanced Microcontroller-based Audio Workshop
+// 
+// Part 1-5: Respond to Pushbuttons & Volume Knob
+//
+// Do more while playing.  Monitor pushbuttons and adjust
+// the volume.  Whe the buttons are pressed, stop playing
+// the current file and skip to the next or previous.
+
+#include <Audio.h>
+#include <Wire.h>
+#include <SPI.h>
+#include <SD.h>
+#include <SerialFlash.h>
+#include <Bounce.h>
+
+AudioPlaySdWav           playSdWav1;
+AudioOutputI2S           i2s1;
+AudioConnection          patchCord1(playSdWav1, 0, i2s1, 0);
+AudioConnection          patchCord2(playSdWav1, 1, i2s1, 1);
+AudioControlSGTL5000     sgtl5000_1;
+
+Bounce button0 = Bounce(0, 15);
+Bounce button2 = Bounce(2, 15);  // 15 = 15 ms debounce time
+
+void setup() {
+  Serial.begin(9600);
+  AudioMemory(8);
+  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(2, INPUT_PULLUP);
+  delay(1000);
+}
+
+int filenumber = 0;  // while file to play
+
+const char * filelist[4] = {
+  "SDTEST1.WAV", "SDTEST2.WAV", "SDTEST3.WAV", "SDTEST4.WAV"
+};
+
+elapsedMillis blinkTime;
+
+void loop() {
+  
+  if (playSdWav1.isPlaying() == false) {
+    const char *filename = filelist[filenumber];
+    filenumber = filenumber + 1;
+    if (filenumber >= 4) filenumber = 0;
+    Serial.print("Start playing ");
+    Serial.println(filename);
+    playSdWav1.play(filename);
+    delay(10); // wait for library to parse WAV info
+  }
+  
+  // blink the LED without delays
+  if (blinkTime < 250) {
+    digitalWrite(13, LOW);
+  } else if (blinkTime < 500) {
+    digitalWrite(13, HIGH);
+  } else {
+    blinkTime = 0; // start blink cycle over again
+  }
+  
+  // read pushbuttons
+  button0.update();
+  if (button0.fallingEdge()) {
+    playSdWav1.stop();
+  }
+  button2.update();
+  if (button2.fallingEdge()) {
+    playSdWav1.stop();
+    filenumber = filenumber - 2;
+    if (filenumber < 0) filenumber = filenumber + 4;
+  }
+  
+  // read the knob position (analog input A2)
+  int knob = analogRead(A2);
+  float vol = (float)knob / 1280.0;
+  sgtl5000_1.volume(vol);
+  //Serial.print("volume = ");
+  //Serial.println(vol);
+}
+
+
+
+