Teensy 4.0 - based Audio Guestbook

Hello everyone,
followed this thread but find no answer to my problem of my second audio guestbook:
my .wav-files just recording nearly the half the recordings.

Hardware is the same like audio guestbook no.1:
Teensy Audio Shield
Teensy 4.1
electret microphone
SD Card SanDisk

all the same versions.
Changing the new Teensy 4.1 with the old one solved the problem, so the code of the new Teensy 4.1 should be the problem right?
I am stuck at the moment because I don't know which settings i should change in the code.

Do you have any idea? Thanks a lot in advance!
 
I have just breadboarded this with a view to installing into an old bakelite phone. I am using a Teensy 4 with a RevD audio board. In all the various versions I have looked at, each defines the SD pins as CS = 10, MOSI = 7, SCK = 14, but these are the pins for the RevC audio boards. I have changed them in my sketch to MOSI = 11, SCK = 13 (CS stays at 10). Perhaps this has been the cause of some of the problems others have seen, and could also explain why it seems to work better with a Teensy 4.1 internal SD card.
Teensy Audio Boards.jpg

See also: https://www.pjrc.com/store/teensy3_audio.html

It's working perfectly so far.
 
Wiring diagram - mic and speaker sharing ground. I'd like to use the original cord from my phone to headset. There are only three wires. Mic, speaker, ground (shared).
The audio shield has a warning:
"Caution: do not short VGND to GND"

Any tips on wiring into audio shield so ground can be shared?
By using capacitors in the headphone lead, it is possible to reference the signal to true gnd. See this diagram from the datasheet.

SGTL5000.jpg

For this project, I would suggest lower value capacitors, perhaps 47uF 10V, as deep bass is not required.
 
I'd like to hear low level microphone in the earpiece (like a normal phone). I thought this would be easy by adding an output from i2s2 into mixer input 4, but it doesn't seem to work. Any workarounds would be gratefully received.
 
Hi, can anyone suggest how to go about adding an audio recording timeout in the code? Occasionally people aren't replacing the handset properly and so I'm getting huge recordings. Not sure if this is a simple fix or not? Thanks, J.
 
Hi, can anyone suggest how to go about adding an audio recording timeout in the code? Occasionally people aren't replacing the handset properly and so I'm getting huge recordings. Not sure if this is a simple fix or not? Thanks, J.
Implemented in my updates to the code. You can either change the default 2 minute timeout at line 55 of audio-guestbook.ino, or edit the gbkcfg.txt file and put that on your SD card.
 
Hello all! I just completed the project and found an issue with the risingEdge and fallingEdge functions. Basically for some strange reason my phone behaves the opposite, so when I hang up it plays the greetings and records, when I pick up the phone it's idle. I tried reversing the two functions, but nada. I will paste here the code with some images too. Is there a way to fix that? Thanks for any help!

Edit: I tried changing the fallingEdge at 171 with a risingEdge, and now it plays when I pick up the phone but only for a split second. Then it abruptly stops =( not sure why. Could it be an electrical issue?

IMG_20231204_182021-min.jpg
IMG_20231204_182005-min.jpg


Code:
/**
 * Audio Guestbook, Copyright (c) 2022 Playful Technology
 *
 * Tested using a Teensy 4.0 with Teensy Audio Shield, although should work
 * with minor modifications on other similar hardware
 *
 * When handset is lifted, a pre-recorded greeting message is played, followed by a tone.
 * Then, recording starts, and continues until the handset is replaced.
 * Playback button allows all messages currently saved on SD card through earpiece
 *
 * Files are saved on SD card as 44.1kHz, 16-bit, mono signed integer RAW audio format
 * --> changed this to WAV recording, DD4WH 2022_07_31
 * --> added MTP support, which enables copying WAV files from the SD card via the USB connection, DD4WH 2022_08_01
 *
 *
 * Frank DD4WH, August 1st 2022
 * for a DBP 611 telephone (closed contact when handheld is lifted) & with recording to WAV file
 * contact for switch button 0 is closed when handheld is lifted
 *
 * GNU GPL v3.0 license
 *
 */

#include <Bounce.h>
#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <TimeLib.h>
#include <MTP_Teensy.h>
#include "play_sd_wav.h" // local copy with fixes

// DEFINES
// Define pins used by Teensy Audio Shield
#define SDCARD_CS_PIN    10
#define SDCARD_MOSI_PIN  7
#define SDCARD_SCK_PIN   14
// And those used for inputs
#define HOOK_PIN 0
#define PLAYBACK_BUTTON_PIN 1

#define noINSTRUMENT_SD_WRITE

// GLOBALS
// Audio initialisation code can be generated using the GUI interface at https://www.pjrc.com/teensy/gui/
// Inputs
AudioSynthWaveform          waveform1; // To create the "beep" sfx
AudioInputI2S               i2s2; // I2S input from microphone on audio shield
AudioPlaySdWavX              playWav1; // Play 44.1kHz 16-bit PCM greeting WAV file
AudioRecordQueue            queue1; // Creating an audio buffer in memory before saving to SD
AudioMixer4                 mixer; // Allows merging several inputs to same output
AudioOutputI2S              i2s1; // I2S interface to Speaker/Line Out on Audio shield
AudioConnection patchCord1(waveform1, 0, mixer, 0); // wave to mixer
AudioConnection patchCord3(playWav1, 0, mixer, 1); // wav file playback mixer
AudioConnection patchCord4(mixer, 0, i2s1, 0); // mixer output to speaker (L)
AudioConnection patchCord6(mixer, 0, i2s1, 1); // mixer output to speaker (R)
AudioConnection patchCord5(i2s2, 0, queue1, 0); // mic input to queue (L)
AudioControlSGTL5000      sgtl5000_1;

// Filename to save audio recording on SD card
char filename[15];
// The file object itself
File frec;

// Use long 40ms debounce time on both switches
Bounce buttonRecord = Bounce(HOOK_PIN, 40);
Bounce buttonPlay = Bounce(PLAYBACK_BUTTON_PIN, 40);

// Keep track of current state of the device
enum Mode {Initialising, Ready, Prompting, Recording, Playing};
Mode mode = Mode::Initialising;

float beep_volume = 0.04f; // not too loud :-)

uint32_t MTPcheckInterval; // default value of device check interval [ms]

// variables for writing to WAV file
unsigned long ChunkSize = 0L;
unsigned long Subchunk1Size = 16;
unsigned int AudioFormat = 1;
unsigned int numChannels = 1;
unsigned long sampleRate = 44100;
unsigned int bitsPerSample = 16;
unsigned long byteRate = sampleRate*numChannels*(bitsPerSample/8);// samplerate x channels x (bitspersample / 8)
unsigned int blockAlign = numChannels*bitsPerSample/8;
unsigned long Subchunk2Size = 0L;
unsigned long recByteSaved = 0L;
unsigned long NumSamples = 0L;
byte byte1, byte2, byte3, byte4;


void setup() {

  Serial.begin(9600);
  while (!Serial && millis() < 5000) {
    // wait for serial port to connect.
  }
  Serial.println("Serial set up correctly");
  Serial.printf("Audio block set to %d samples\n",AUDIO_BLOCK_SAMPLES);
  print_mode();
  // Configure the input pins
  pinMode(HOOK_PIN, INPUT_PULLUP);
  pinMode(PLAYBACK_BUTTON_PIN, INPUT_PULLUP);

  // Audio connections require memory, and the record queue
  // uses this memory to buffer incoming audio.
  AudioMemory(60);

  // Enable the audio shield, select input, and enable output
  sgtl5000_1.enable();
  // Define which input on the audio shield to use (AUDIO_INPUT_LINEIN / AUDIO_INPUT_MIC)
  sgtl5000_1.inputSelect(AUDIO_INPUT_MIC);
  //sgtl5000_1.adcHighPassFilterDisable(); //
  sgtl5000_1.volume(0.95);

  mixer.gain(0, 1.0f);
  mixer.gain(1, 1.0f);

  // Play a beep to indicate system is online
  waveform1.begin(beep_volume, 440, WAVEFORM_SINE);
  wait(1000);
  waveform1.amplitude(0);
  delay(1000);

  // Initialize the SD card
  SPI.setMOSI(SDCARD_MOSI_PIN);
  SPI.setSCK(SDCARD_SCK_PIN);
  if (!(SD.begin(SDCARD_CS_PIN)))
  {
    // stop here if no SD card, but print a message
    while (1) {
      Serial.println("Unable to access the SD card");
      delay(500);
    }
  }
    else Serial.println("SD card correctly initialized");


  // mandatory to begin the MTP session.
    MTP.begin();

  // Add SD Card
//    MTP.addFilesystem(SD, "SD Card");
    MTP.addFilesystem(SD, "Kais Audio guestbook"); // choose a nice name for the SD card volume to appear in your file explorer
    Serial.println("Added SD card via MTP");
    MTPcheckInterval = MTP.storage()->get_DeltaDeviceCheckTimeMS();
   
    // Value in dB
//  sgtl5000_1.micGain(15);
  sgtl5000_1.micGain(5); // much lower gain is required for the AOM5024 electret capsule

  // Synchronise the Time object used in the program code with the RTC time provider.
  // See https://github.com/PaulStoffregen/Time
  setSyncProvider(getTeensy3Time);
 
  // Define a callback that will assign the correct datetime for any file system operations
  // (i.e. saving a new audio recording onto the SD card)
  FsDateTime::setCallback(dateTime);

  mode = Mode::Ready; print_mode();
}

void loop() {
  // First, read the buttons
  buttonRecord.update();
  buttonPlay.update();

  switch(mode){
    case Mode::Ready:
      // Falling edge occurs when the handset is lifted --> 611 telephone
      if (buttonRecord.fallingEdge()) {
        Serial.println("Handset lifted");
        mode = Mode::Prompting; print_mode();
      }
      else if(buttonPlay.fallingEdge()) {
        //playAllRecordings();
        playLastRecording();
      }
      break;

    case Mode::Prompting:
      // Wait a second for users to put the handset to their ear
      wait(1000);
      // Play the greeting inviting them to record their message
      playWav1.play("greeting.wav");  
      // Wait until the  message has finished playing
//      while (playWav1.isPlaying()) {
      while (!playWav1.isStopped()) {
        // Check whether the handset is replaced
        buttonRecord.update();
        buttonPlay.update();
        // Handset is replaced
        if(buttonRecord.risingEdge()) {
          playWav1.stop();
          mode = Mode::Ready; print_mode();
          return;
        }
        if(buttonPlay.fallingEdge()) {
          playWav1.stop();
          //playAllRecordings();
          playLastRecording();
          return;
        }
       
      }
      // Debug message
      Serial.println("Starting Recording");
      // Play the tone sound effect
      waveform1.begin(beep_volume, 440, WAVEFORM_SINE);
      wait(1250);
      waveform1.amplitude(0);
      // Start the recording function
      startRecording();
      break;

    case Mode::Recording:
      // Handset is replaced
      if(buttonRecord.risingEdge()){
        // Debug log
        Serial.println("Stopping Recording");
        // Stop recording
        stopRecording();
        // Play audio tone to confirm recording has ended
        end_Beep();
      }
      else {
        continueRecording();
      }
      break;

    case Mode::Playing: // to make compiler happy
      break;

    case Mode::Initialising: // to make compiler happy
      break;
  }  
 
  MTP.loop();  // This is mandatory to be placed in the loop code.
}

void setMTPdeviceChecks(bool nable)
{
  if (nable)
  {
    MTP.storage()->set_DeltaDeviceCheckTimeMS(MTPcheckInterval);
    Serial.print("En");
  }
  else
  {
    MTP.storage()->set_DeltaDeviceCheckTimeMS((uint32_t) -1);
    Serial.print("Dis");
  }
  Serial.println("abled MTP storage device checks");
}
 

#if defined(INSTRUMENT_SD_WRITE)
static uint32_t worstSDwrite, printNext;
#endif // defined(INSTRUMENT_SD_WRITE)

void startRecording() {
  setMTPdeviceChecks(false); // disable MTP device checks while recording
#if defined(INSTRUMENT_SD_WRITE)
  worstSDwrite = 0;
  printNext = 0;
#endif // defined(INSTRUMENT_SD_WRITE)
  // Find the first available file number
//  for (uint8_t i=0; i<9999; i++) { // BUGFIX uint8_t overflows if it reaches 255
  for (uint16_t i=0; i<9999; i++) {  
    // Format the counter as a five-digit number with leading zeroes, followed by file extension
    snprintf(filename, 11, " %05d.wav", i);
    // Create if does not exist, do not open existing, write, sync after write
    if (!SD.exists(filename)) {
      break;
    }
  }
  frec = SD.open(filename, FILE_WRITE);
  Serial.println("Opened file !");
  if(frec) {
    Serial.print("Recording to ");
    Serial.println(filename);
    queue1.begin();
    mode = Mode::Recording; print_mode();
    recByteSaved = 0L;
  }
  else {
    Serial.println("Couldn't open file to record!");
  }
}

void continueRecording() {
#if defined(INSTRUMENT_SD_WRITE)
  uint32_t started = micros();
#endif // defined(INSTRUMENT_SD_WRITE)
#define NBLOX 16
  // Check if there is data in the queue
  if (queue1.available() >= NBLOX) {
    byte buffer[NBLOX*AUDIO_BLOCK_SAMPLES*sizeof(int16_t)];
    // Fetch 2 blocks from the audio library and copy
    // into a 512 byte buffer.  The Arduino SD library
    // is most efficient when full 512 byte sector size
    // writes are used.
    for (int i=0;i<NBLOX;i++)
    {
      memcpy(buffer+i*AUDIO_BLOCK_SAMPLES*sizeof(int16_t), queue1.readBuffer(), AUDIO_BLOCK_SAMPLES*sizeof(int16_t));
      queue1.freeBuffer();
    }
    // Write all 512 bytes to the SD card
    frec.write(buffer, sizeof buffer);
    recByteSaved += sizeof buffer;
  }
 
#if defined(INSTRUMENT_SD_WRITE)
  started = micros() - started;
  if (started > worstSDwrite)
    worstSDwrite = started;

  if (millis() >= printNext)
  {
    Serial.printf("Worst write took %luus\n",worstSDwrite);
    worstSDwrite = 0;
    printNext = millis()+250;
  }
#endif // defined(INSTRUMENT_SD_WRITE)
}

void stopRecording() {
  // Stop adding any new data to the queue
  queue1.end();
  // Flush all existing remaining data from the queue
  while (queue1.available() > 0) {
    // Save to open file
    frec.write((byte*)queue1.readBuffer(), AUDIO_BLOCK_SAMPLES*sizeof(int16_t));
    queue1.freeBuffer();
    recByteSaved += AUDIO_BLOCK_SAMPLES*sizeof(int16_t);
  }
  writeOutHeader();
  // Close the file
  frec.close();
  Serial.println("Closed file");
  mode = Mode::Ready; print_mode();
  setMTPdeviceChecks(true); // enable MTP device checks, recording is finished
}


void playAllRecordings() {
  // Recording files are saved in the root directory
  File dir = SD.open("/");
 
  while (true) {
    File entry =  dir.openNextFile();
    if (strstr(entry.name(), "greeting"))
    {
       entry =  dir.openNextFile();
    }
    if (!entry) {
      // no more files
      entry.close();
      end_Beep();
      break;
    }
    //int8_t len = strlen(entry.name()) - 4;
//    if (strstr(strlwr(entry.name() + (len - 4)), ".raw")) {
//    if (strstr(strlwr(entry.name() + (len - 4)), ".wav")) {
    // the lines above throw a warning, so I replace them with this (which is also easier to read):
    if (strstr(entry.name(), ".wav") || strstr(entry.name(), ".WAV")) {
      Serial.print("Now playing ");
      Serial.println(entry.name());
      // Play a short beep before each message
      waveform1.amplitude(beep_volume);
      wait(750);
      waveform1.amplitude(0);
      // Play the file
      playWav1.play(entry.name());
      mode = Mode::Playing; print_mode();
    }
    entry.close();

//    while (playWav1.isPlaying()) { // strangely enough, this works for playRaw, but it does not work properly for playWav
    while (!playWav1.isStopped()) { // this works for playWav
      buttonPlay.update();
      buttonRecord.update();
      // Button is pressed again
//      if(buttonPlay.risingEdge() || buttonRecord.risingEdge()) { // FIX
      if(buttonPlay.fallingEdge() || buttonRecord.risingEdge()) {
        playWav1.stop();
        mode = Mode::Ready; print_mode();
        return;
      }  
    }
  }
  // All files have been played
  mode = Mode::Ready; print_mode();
}

void playLastRecording() {
  // Find the first available file number
  uint16_t idx = 0;
  for (uint16_t i=0; i<9999; i++) {
    // Format the counter as a five-digit number with leading zeroes, followed by file extension
    snprintf(filename, 11, " %05d.wav", i);
    // check, if file with index i exists
    if (!SD.exists(filename)) {
     idx = i - 1;
     break;
      }
  }
      // now play file with index idx == last recorded file
      snprintf(filename, 11, " %05d.wav", idx);
      Serial.println(filename);
      playWav1.play(filename);
      mode = Mode::Playing; print_mode();
      while (!playWav1.isStopped()) { // this works for playWav
      buttonPlay.update();
      buttonRecord.update();
      // Button is pressed again
//      if(buttonPlay.risingEdge() || buttonRecord.risingEdge()) { // FIX
      if(buttonPlay.fallingEdge() || buttonRecord.risingEdge()) {
        playWav1.stop();
        mode = Mode::Ready; print_mode();
        return;
      }  
    }
      // file has been played
  mode = Mode::Ready; print_mode();
  end_Beep();
}


// Retrieve the current time from Teensy built-in RTC
time_t getTeensy3Time(){
  return Teensy3Clock.get();
}

// Callback to assign timestamps for file system operations
void dateTime(uint16_t* date, uint16_t* time, uint8_t* ms10) {

  // Return date using FS_DATE macro to format fields.
  *date = FS_DATE(year(), month(), day());

  // Return time using FS_TIME macro to format fields.
  *time = FS_TIME(hour(), minute(), second());

  // Return low time bits in units of 10 ms.
  *ms10 = second() & 1 ? 100 : 0;
}

// Non-blocking delay, which pauses execution of main program logic,
// but while still listening for input
void wait(unsigned int milliseconds) {
  elapsedMillis msec=0;

  while (msec <= milliseconds) {
    buttonRecord.update();
    buttonPlay.update();
    if (buttonRecord.fallingEdge()) Serial.println("Button (pin 0) Press");
    if (buttonPlay.fallingEdge()) Serial.println("Button (pin 1) Press");
    if (buttonRecord.risingEdge()) Serial.println("Button (pin 0) Release");
    if (buttonPlay.risingEdge()) Serial.println("Button (pin 1) Release");
  }
}


void writeOutHeader() { // update WAV header with final filesize/datasize

//  NumSamples = (recByteSaved*8)/bitsPerSample/numChannels;
//  Subchunk2Size = NumSamples*numChannels*bitsPerSample/8; // number of samples x number of channels x number of bytes per sample
  Subchunk2Size = recByteSaved - 42; // because we didn't make space for the header to start with! Lose 21 samples...
  ChunkSize = Subchunk2Size + 34; // was 36;
  frec.seek(0);
  frec.write("RIFF");
  byte1 = ChunkSize & 0xff;
  byte2 = (ChunkSize >> 8) & 0xff;
  byte3 = (ChunkSize >> 16) & 0xff;
  byte4 = (ChunkSize >> 24) & 0xff;
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  frec.write("WAVE");
  frec.write("fmt ");
  byte1 = Subchunk1Size & 0xff;
  byte2 = (Subchunk1Size >> 8) & 0xff;
  byte3 = (Subchunk1Size >> 16) & 0xff;
  byte4 = (Subchunk1Size >> 24) & 0xff;
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  byte1 = AudioFormat & 0xff;
  byte2 = (AudioFormat >> 8) & 0xff;
  frec.write(byte1);  frec.write(byte2);
  byte1 = numChannels & 0xff;
  byte2 = (numChannels >> 8) & 0xff;
  frec.write(byte1);  frec.write(byte2);
  byte1 = sampleRate & 0xff;
  byte2 = (sampleRate >> 8) & 0xff;
  byte3 = (sampleRate >> 16) & 0xff;
  byte4 = (sampleRate >> 24) & 0xff;
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  byte1 = byteRate & 0xff;
  byte2 = (byteRate >> 8) & 0xff;
  byte3 = (byteRate >> 16) & 0xff;
  byte4 = (byteRate >> 24) & 0xff;
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  byte1 = blockAlign & 0xff;
  byte2 = (blockAlign >> 8) & 0xff;
  frec.write(byte1);  frec.write(byte2);
  byte1 = bitsPerSample & 0xff;
  byte2 = (bitsPerSample >> 8) & 0xff;
  frec.write(byte1);  frec.write(byte2);
  frec.write("data");
  byte1 = Subchunk2Size & 0xff;
  byte2 = (Subchunk2Size >> 8) & 0xff;
  byte3 = (Subchunk2Size >> 16) & 0xff;
  byte4 = (Subchunk2Size >> 24) & 0xff;
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  frec.close();
  Serial.println("header written");
  Serial.print("Subchunk2: ");
  Serial.println(Subchunk2Size);
}

void end_Beep(void) {
          waveform1.frequency(523.25);
        waveform1.amplitude(beep_volume);
        wait(250);
        waveform1.amplitude(0);
        wait(250);
        waveform1.amplitude(beep_volume);
        wait(250);
        waveform1.amplitude(0);
        wait(250);
        waveform1.amplitude(beep_volume);
        wait(250);
        waveform1.amplitude(0);
        wait(250);
        waveform1.amplitude(beep_volume);
        wait(250);
        waveform1.amplitude(0);
}

void print_mode(void) { // only for debugging
  Serial.print("Mode switched to: ");
  // Initialising, Ready, Prompting, Recording, Playing
  if(mode == Mode::Ready)           Serial.println(" Ready");
  else if(mode == Mode::Prompting)  Serial.println(" Prompting");
  else if(mode == Mode::Recording)  Serial.println(" Recording");
  else if(mode == Mode::Playing)    Serial.println(" Playing");
  else if(mode == Mode::Initialising)  Serial.println(" Initialising");
  else Serial.println(" Undefined");
}
 
Last edited:
Edit: I tried changing the fallingEdge at 171 with a risingEdge, and now it plays when I pick up the phone but only for a split second. Then it abruptly stops =( not sure why. Could it be an electrical issue?

That is correct, you have only adjusted the first instance in which it is checking the input buttonRecord to see when the handset is lifted. There are many other IF statements used to see when the handset is replaced. You will need to adjust these also.
 
Hello everyone I know this is an older post but I'm hoping to get some help. I followed the original video and have my teensy board together and connected to the phone and using the latest sketch. the phone beeps once when it is connected to power and I can hear an audio click when the hook is either pushed down or released but nothing else. I have our greeting message saved as a wave file on the SD card but that doesn't play nor does anything get recorded onto their. I was thinking maybe i soldered into the wrong hook pins but then why is there that audio change. I've uploaded the sketch that I have and hit upload which tells me it completes and then opens the loader which programs and reboots. I'm definitely a novice with this board as I got it for this project but could use some help please.
Code:
[code]
/**
 * Audio Guestbook, Copyright (c) 2022 Playful Technology
 *
 * Tested using a Teensy 4.0 with Teensy Audio Shield, although should work
 * with minor modifications on other similar hardware
 *
 * When handset is lifted, a pre-recorded greeting message is played, followed by a tone.
 * Then, recording starts, and continues until the handset is replaced.
 * Playback button allows all messages currently saved on SD card through earpiece
 *
 * Files are saved on SD card as 44.1kHz, 16-bit, mono signed integer RAW audio format
 * --> changed this to WAV recording, DD4WH 2022_07_31
 * --> added MTP support, which enables copying WAV files from the SD card via the USB connection, DD4WH 2022_08_01
 *
 *
 * Frank DD4WH, August 1st 2022
 * for a DBP 611 telephone (closed contact when handheld is lifted) & with recording to WAV file
 * contact for switch button 0 is closed when handheld is lifted
 *
 * GNU GPL v3.0 license
 *
 */

#include <Bounce.h>
#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <TimeLib.h>
#include <MTP_Teensy.h>
#include "play_sd_wav.h" // local copy with fixes

// DEFINES
// Define pins used by Teensy Audio Shield
#define SDCARD_CS_PIN    10
#define SDCARD_MOSI_PIN  7
#define SDCARD_SCK_PIN   14
// And those used for inputs
#define HOOK_PIN 0
#define PLAYBACK_BUTTON_PIN 1

#define noINSTRUMENT_SD_WRITE

// GLOBALS
// Audio initialisation code can be generated using the GUI interface at https://www.pjrc.com/teensy/gui/
// Inputs
AudioSynthWaveform          waveform1; // To create the "beep" sfx
AudioInputI2S               i2s2; // I2S input from microphone on audio shield
AudioPlaySdWav              playWav1; // Play 44.1kHz 16-bit PCM greeting WAV file
AudioRecordQueue            queue1; // Creating an audio buffer in memory before saving to SD
AudioMixer4                 mixer; // Allows merging several inputs to same output
AudioOutputI2S              i2s1; // I2S interface to Speaker/Line Out on Audio shield
AudioConnection patchCord1(waveform1, 0, mixer, 0); // wave to mixer
AudioConnection patchCord3(playWav1, 0, mixer, 1); // wav file playback mixer
AudioConnection patchCord4(mixer, 0, i2s1, 0); // mixer output to speaker (L)
AudioConnection patchCord6(mixer, 0, i2s1, 1); // mixer output to speaker (R)
AudioConnection patchCord5(i2s2, 0, queue1, 0); // mic input to queue (L)
AudioControlSGTL5000      sgtl5000_1;

// Filename to save audio recording on SD card
char filename[15];
// The file object itself
File frec;

// Use long 40ms debounce time on both switches
Bounce buttonRecord = Bounce(HOOK_PIN, 40);
Bounce buttonPlay = Bounce(PLAYBACK_BUTTON_PIN, 40);

// Keep track of current state of the device
enum Mode {Initialising, Ready, Prompting, Recording, Playing};
Mode mode = Mode::Initialising;

float beep_volume = 0.04f; // not too loud :-)

uint32_t MTPcheckInterval; // default value of device check interval [ms]

// variables for writing to WAV file
unsigned long ChunkSize = 0L;
unsigned long Subchunk1Size = 16;
unsigned int AudioFormat = 1;
unsigned int numChannels = 1;
unsigned long sampleRate = 44100;
unsigned int bitsPerSample = 16;
unsigned long byteRate = sampleRate*numChannels*(bitsPerSample/8);// samplerate x channels x (bitspersample / 8)
unsigned int blockAlign = numChannels*bitsPerSample/8;
unsigned long Subchunk2Size = 0L;
unsigned long recByteSaved = 0L;
unsigned long NumSamples = 0L;
byte byte1, byte2, byte3, byte4;


void setup() {

  Serial.begin(9600);
  while (!Serial && millis() < 5000) {
    // wait for serial port to connect.
  }
  Serial.println("Serial set up correctly");
  Serial.printf("Audio block set to %d samples\n",AUDIO_BLOCK_SAMPLES);
  print_mode();
  // Configure the input pins
  pinMode(HOOK_PIN, INPUT_PULLUP);
  pinMode(PLAYBACK_BUTTON_PIN, INPUT_PULLUP);

  // Audio connections require memory, and the record queue
  // uses this memory to buffer incoming audio.
  AudioMemory(60);

  // Enable the audio shield, select input, and enable output
  sgtl5000_1.enable();
  // Define which input on the audio shield to use (AUDIO_INPUT_LINEIN / AUDIO_INPUT_MIC)
  sgtl5000_1.inputSelect(AUDIO_INPUT_MIC);
  //sgtl5000_1.adcHighPassFilterDisable(); //
  sgtl5000_1.volume(0.95);

  mixer.gain(0, 1.0f);
  mixer.gain(1, 1.0f);

  // Play a beep to indicate system is online
  waveform1.begin(beep_volume, 440, WAVEFORM_SINE);
  wait(1000);
  waveform1.amplitude(0);
  delay(1000);

  // Initialize the SD card
  SPI.setMOSI(SDCARD_MOSI_PIN);
  SPI.setSCK(SDCARD_SCK_PIN);
  if (!(SD.begin(SDCARD_CS_PIN)))
  {
    // stop here if no SD card, but print a message
    while (1) {
      Serial.println("Unable to access the SD card");
      delay(500);
    }
  }
    else Serial.println("SD card correctly initialized");


  // mandatory to begin the MTP session.
    MTP.begin();

  // Add SD Card
//    MTP.addFilesystem(SD, "SD Card");
    MTP.addFilesystem(SD, "Adams Audio guestbook"); // choose a nice name for the SD card volume to appear in your file explorer
    Serial.println("Added SD card via MTP");
    MTPcheckInterval = MTP.storage()->get_DeltaDeviceCheckTimeMS();
    
    // Value in dB
//  sgtl5000_1.micGain(15);
  sgtl5000_1.micGain(5); // much lower gain is required for the AOM5024 electret capsule

  // Synchronise the Time object used in the program code with the RTC time provider.
  // See https://github.com/PaulStoffregen/Time
  setSyncProvider(getTeensy3Time);
 
  // Define a callback that will assign the correct datetime for any file system operations
  // (i.e. saving a new audio recording onto the SD card)
  FsDateTime::setCallback(dateTime);

  mode = Mode::Ready; print_mode();
}

void loop() {
  // First, read the buttons
  buttonRecord.update();
  buttonPlay.update();

  switch(mode){
    case Mode::Ready:
      // Falling edge occurs when the handset is lifted --> 611 telephone
      if (buttonRecord.fallingEdge()) {
        Serial.println("Handset lifted");
        mode = Mode::Prompting; print_mode();
      }
      else if(buttonPlay.fallingEdge()) {
        //playAllRecordings();
        playLastRecording();
      }
      break;

    case Mode::Prompting:
      // Wait a second for users to put the handset to their ear
      wait(1500);
      // Play the greeting inviting them to record their message
      playWav1.play("greeting.wav");   
      // Wait until the  message has finished playing
//      while (playWav1.isPlaying()) {
      while (!playWav1.isStopped()) {
        // Check whether the handset is replaced
        buttonRecord.update();
        buttonPlay.update();
        // Handset is replaced
        if(buttonRecord.fallingEdge()) {
          playWav1.stop();
          mode = Mode::Ready; print_mode();
          return;
        }
        if(buttonPlay.risingEdge()) {
          playWav1.stop();
          //playAllRecordings();
          playLastRecording();
          return;
        }
        
      }
      // Debug message
      Serial.println("Starting Recording");
      // Play the tone sound effect
      waveform1.begin(beep_volume, 440, WAVEFORM_SINE);
      wait(1250);
      waveform1.amplitude(0);
      // Start the recording function
      startRecording();
      break;

    case Mode::Recording:
      // Handset is replaced
      if(buttonRecord.fallingEdge()){
        // Debug log
        Serial.println("Stopping Recording");
        // Stop recording
        stopRecording();
        // Play audio tone to confirm recording has ended
        end_Beep();
      }
      else {
        continueRecording();
      }
      break;

    case Mode::Playing: // to make compiler happy
      break; 

    case Mode::Initialising: // to make compiler happy
      break; 
  }   
 
  MTP.loop();  // This is mandatory to be placed in the loop code.
}

void setMTPdeviceChecks(bool nable)
{
  if (nable)
  {
    MTP.storage()->set_DeltaDeviceCheckTimeMS(MTPcheckInterval);
    Serial.print("En");
  }
  else
  {
    MTP.storage()->set_DeltaDeviceCheckTimeMS((uint32_t) -1);
    Serial.print("Dis");
  }
  Serial.println("abled MTP storage device checks");
}
 

#if defined(INSTRUMENT_SD_WRITE)
static uint32_t worstSDwrite, printNext;
#endif // defined(INSTRUMENT_SD_WRITE)

void startRecording() {
  setMTPdeviceChecks(false); // disable MTP device checks while recording
#if defined(INSTRUMENT_SD_WRITE)
  worstSDwrite = 0;
  printNext = 0;
#endif // defined(INSTRUMENT_SD_WRITE)
  // Find the first available file number
//  for (uint8_t i=0; i<9999; i++) { // BUGFIX uint8_t overflows if it reaches 255 
  for (uint16_t i=0; i<9999; i++) {   
    // Format the counter as a five-digit number with leading zeroes, followed by file extension
    snprintf(filename, 11, " %05d.wav", i);
    // Create if does not exist, do not open existing, write, sync after write
    if (!SD.exists(filename)) {
      break;
    }
  }
  frec = SD.open(filename, FILE_WRITE);
  Serial.println("Opened file !");
  if(frec) {
    Serial.print("Recording to ");
    Serial.println(filename);
    queue1.begin();
    mode = Mode::Recording; print_mode();
    recByteSaved = 0L;
  }
  else {
    Serial.println("Couldn't open file to record!");
  }
}

void continueRecording() {
#if defined(INSTRUMENT_SD_WRITE)
  uint32_t started = micros();
#endif // defined(INSTRUMENT_SD_WRITE)
#define NBLOX 16 
  // Check if there is data in the queue
  if (queue1.available() >= NBLOX) {
    byte buffer[NBLOX*AUDIO_BLOCK_SAMPLES*sizeof(int16_t)];
    // Fetch 2 blocks from the audio library and copy
    // into a 512 byte buffer.  The Arduino SD library
    // is most efficient when full 512 byte sector size
    // writes are used.
    for (int i=0;i<NBLOX;i++)
    {
      memcpy(buffer+i*AUDIO_BLOCK_SAMPLES*sizeof(int16_t), queue1.readBuffer(), AUDIO_BLOCK_SAMPLES*sizeof(int16_t));
      queue1.freeBuffer();
    }
    // Write all 512 bytes to the SD card
    frec.write(buffer, sizeof buffer);
    recByteSaved += sizeof buffer;
  }
 
#if defined(INSTRUMENT_SD_WRITE)
  started = micros() - started;
  if (started > worstSDwrite)
    worstSDwrite = started;

  if (millis() >= printNext)
  {
    Serial.printf("Worst write took %luus\n",worstSDwrite);
    worstSDwrite = 0;
    printNext = millis()+250;
  }
#endif // defined(INSTRUMENT_SD_WRITE)
}

void stopRecording() {
  // Stop adding any new data to the queue
  queue1.end();
  // Flush all existing remaining data from the queue
  while (queue1.available() > 0) {
    // Save to open file
    frec.write((byte*)queue1.readBuffer(), AUDIO_BLOCK_SAMPLES*sizeof(int16_t));
    queue1.freeBuffer();
    recByteSaved += AUDIO_BLOCK_SAMPLES*sizeof(int16_t);
  }
  writeOutHeader();
  // Close the file
  frec.close();
  Serial.println("Closed file");
  mode = Mode::Ready; print_mode();
  setMTPdeviceChecks(true); // enable MTP device checks, recording is finished
}


void playAllRecordings() {
  // Recording files are saved in the root directory
  File dir = SD.open("/");
 
  while (true) {
    File entry =  dir.openNextFile();
    if (strstr(entry.name(), "greeting"))
    {
       entry =  dir.openNextFile();
    }
    if (!entry) {
      // no more files
      entry.close();
      end_Beep();
      break;
    }
    //int8_t len = strlen(entry.name()) - 4;
//    if (strstr(strlwr(entry.name() + (len - 4)), ".raw")) {
//    if (strstr(strlwr(entry.name() + (len - 4)), ".wav")) {
    // the lines above throw a warning, so I replace them with this (which is also easier to read):
    if (strstr(entry.name(), ".wav") || strstr(entry.name(), ".WAV")) {
      Serial.print("Now playing ");
      Serial.println(entry.name());
      // Play a short beep before each message
      waveform1.amplitude(beep_volume);
      wait(750);
      waveform1.amplitude(0);
      // Play the file
      playWav1.play(entry.name());
      mode = Mode::Playing; print_mode();
    }
    entry.close();

//    while (playWav1.isPlaying()) { // strangely enough, this works for playRaw, but it does not work properly for playWav
    while (!playWav1.isStopped()) { // this works for playWav
      buttonPlay.update();
      buttonRecord.update();
      // Button is pressed again
//      if(buttonPlay.fallingEdge() || buttonRecord.fallingEdge()) { // FIX
      if(buttonPlay.risingEdge() || buttonRecord.fallingEdge()) {
        playWav1.stop();
        mode = Mode::Ready; print_mode();
        return;
      }   
    }
  }
  // All files have been played
  mode = Mode::Ready; print_mode();
}

void playLastRecording() {
  // Find the first available file number
  uint16_t idx = 0;
  for (uint16_t i=0; i<9999; i++) {
    // Format the counter as a five-digit number with leading zeroes, followed by file extension
    snprintf(filename, 11, " %05d.wav", i);
    // check, if file with index i exists
    if (!SD.exists(filename)) {
     idx = i - 1;
     break;
      }
  }
      // now play file with index idx == last recorded file
      snprintf(filename, 11, " %05d.wav", idx);
      Serial.println(filename);
      playWav1.play(filename);
      mode = Mode::Playing; print_mode();
      while (!playWav1.isStopped()) { // this works for playWav
      buttonPlay.update();
      buttonRecord.update();
      // Button is pressed again
//      if(buttonPlay.fallingEdge() || buttonRecord.fallingEdge()) { // FIX
      if(buttonPlay.risingEdge() || buttonRecord.fallingEdge()) {
        playWav1.stop();
        mode = Mode::Ready; print_mode();
        return;
      }   
    }
      // file has been played
  mode = Mode::Ready; print_mode(); 
  end_Beep();
}


// Retrieve the current time from Teensy built-in RTC
time_t getTeensy3Time(){
  return Teensy3Clock.get();
}

// Callback to assign timestamps for file system operations
void dateTime(uint16_t* date, uint16_t* time, uint8_t* ms10) {

  // Return date using FS_DATE macro to format fields.
  *date = FS_DATE(year(), month(), day());

  // Return time using FS_TIME macro to format fields.
  *time = FS_TIME(hour(), minute(), second());

  // Return low time bits in units of 10 ms.
  *ms10 = second() & 1 ? 100 : 0;
}

// Non-blocking delay, which pauses execution of main program logic,
// but while still listening for input
void wait(unsigned int milliseconds) {
  elapsedMillis msec=0;

  while (msec <= milliseconds) {
    buttonRecord.update();
    buttonPlay.update();
    if (buttonRecord.risingEdge()) Serial.println("Button (pin 0) Press");
    if (buttonPlay.risingEdge()) Serial.println("Button (pin 1) Press");
    if (buttonRecord.fallingEdge()) Serial.println("Button (pin 0) Release");
    if (buttonPlay.fallingEdge()) Serial.println("Button (pin 1) Release");
  }
}


void writeOutHeader() { // update WAV header with final filesize/datasize

//  NumSamples = (recByteSaved*8)/bitsPerSample/numChannels;
//  Subchunk2Size = NumSamples*numChannels*bitsPerSample/8; // number of samples x number of channels x number of bytes per sample
  Subchunk2Size = recByteSaved - 42; // because we didn't make space for the header to start with! Lose 21 samples...
  ChunkSize = Subchunk2Size + 34; // was 36;
  frec.seek(0);
  frec.write("RIFF");
  byte1 = ChunkSize & 0xff;
  byte2 = (ChunkSize >> 8) & 0xff;
  byte3 = (ChunkSize >> 16) & 0xff;
  byte4 = (ChunkSize >> 24) & 0xff; 
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  frec.write("WAVE");
  frec.write("fmt ");
  byte1 = Subchunk1Size & 0xff;
  byte2 = (Subchunk1Size >> 8) & 0xff;
  byte3 = (Subchunk1Size >> 16) & 0xff;
  byte4 = (Subchunk1Size >> 24) & 0xff; 
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  byte1 = AudioFormat & 0xff;
  byte2 = (AudioFormat >> 8) & 0xff;
  frec.write(byte1);  frec.write(byte2);
  byte1 = numChannels & 0xff;
  byte2 = (numChannels >> 8) & 0xff;
  frec.write(byte1);  frec.write(byte2);
  byte1 = sampleRate & 0xff;
  byte2 = (sampleRate >> 8) & 0xff;
  byte3 = (sampleRate >> 16) & 0xff;
  byte4 = (sampleRate >> 24) & 0xff; 
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  byte1 = byteRate & 0xff;
  byte2 = (byteRate >> 8) & 0xff;
  byte3 = (byteRate >> 16) & 0xff;
  byte4 = (byteRate >> 24) & 0xff; 
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  byte1 = blockAlign & 0xff;
  byte2 = (blockAlign >> 8) & 0xff;
  frec.write(byte1);  frec.write(byte2);
  byte1 = bitsPerSample & 0xff;
  byte2 = (bitsPerSample >> 8) & 0xff;
  frec.write(byte1);  frec.write(byte2);
  frec.write("data");
  byte1 = Subchunk2Size & 0xff;
  byte2 = (Subchunk2Size >> 8) & 0xff;
  byte3 = (Subchunk2Size >> 16) & 0xff;
  byte4 = (Subchunk2Size >> 24) & 0xff; 
  frec.write(byte1);  frec.write(byte2);  frec.write(byte3);  frec.write(byte4);
  frec.close();
  Serial.println("header written");
  Serial.print("Subchunk2: ");
  Serial.println(Subchunk2Size);
}

void end_Beep(void) {
          waveform1.frequency(523.25);
        waveform1.amplitude(beep_volume);
        wait(250);
        waveform1.amplitude(0);
        wait(250);
        waveform1.amplitude(beep_volume);
        wait(250);
        waveform1.amplitude(0);
        wait(250);
        waveform1.amplitude(beep_volume);
        wait(250);
        waveform1.amplitude(0);
        wait(250);
        waveform1.amplitude(beep_volume);
        wait(250);
        waveform1.amplitude(0);
}

void print_mode(void) { // only for debugging
  Serial.print("Mode switched to: ");
  // Initialising, Ready, Prompting, Recording, Playing
  if(mode == Mode::Ready)           Serial.println(" Ready");
  else if(mode == Mode::Prompting)  Serial.println(" Prompting");
  else if(mode == Mode::Recording)  Serial.println(" Recording");
  else if(mode == Mode::Playing)    Serial.println(" Playing");
  else if(mode == Mode::Initialising)  Serial.println(" Initialising");
  else Serial.println(" Undefined");
}
[/CODE]
 
I should also note that I did not add the button to play back the message as I was planning on just taking the SD card out after and using the recordings for a wedding video.
 
I have just breadboarded this with a view to installing into an old bakelite phone. I am using a Teensy 4 with a RevD audio board. In all the various versions I have looked at, each defines the SD pins as CS = 10, MOSI = 7, SCK = 14, but these are the pins for the RevC audio boards. I have changed them in my sketch to MOSI = 11, SCK = 13 (CS stays at 10). Perhaps this has been the cause of some of the problems others have seen, and could also explain why it seems to work better with a Teensy 4.1 internal SD card.
View attachment 32122

See also: https://www.pjrc.com/store/teensy3_audio.html

It's working perfectly so far.
My god... you are a life saver. This worked so well for me now. Thank you so much!

Just moved to a Teensy 4.1 + Audio Rev D board and have mounted this to a custom PCB I designed through EasyEDA. The result is perfect crisp audio on the recordings, even when using a laptop USB port as the power source. Previously, I had to rely on the powerbanks to power it to reduce the static. If anyone does fancy a copy of the gerber file, let me know and I can share with you. 5 boards cost ~ £3.50 delivered and use mostly off the shelf components, like screw terminals and switches.
 
Wiring diagram - mic and speaker sharing ground. I'd like to use the original cord from my phone to headset. There are only three wires. Mic, speaker, ground (shared).
The audio shield has a warning:
"Caution: do not short VGND to GND"

Any tips on wiring into audio shield so ground can be shared?
I had a similar situation where I was wiring an old Western Electric 302 model which has 3 wires:
  • Speaker wire (white to dial)
  • Mic wire (black to dial)
  • Shared wire, used in speaker and mic (R to induction coil)
I tried wiring to the HP with tip to the speaker wire, and Shared to sleeve which worked well.
I wired the mic with G to shared, and mic to mic.
The result was good audio out of the headphone jack but the recorded audio from the mic was super quiet. Only thought was the shared wire was splitting the signal or something (full disclaimer i'm a complete noob).

Instead, given some of the conversations in this thread, I thought to try the Line Out instead of the HP to get away from VGND completely and experimented. I tried wiring Speaker/Shared to L+ and L- and it was a success.
 
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