M5Dial + PDMUnit Sample(Port.B)

main.cpp

#include <M5Unified.h>
#include <SPIFFS.h>
#include <WiFi.h>
#include <WebServer.h>
#include <ESPmDNS.h>

#define SAMPLE_RATE 8000 // Sampling rate
#define CHUNK 1024 // I2S buffer size
#define PERIAD 10 // Recording time (sec)

#define CONFIG_I2S_LRCK_PIN 1 // I2S clock
#define CONFIG_I2S_DATA_IN_PIN 2 // I2S data

// WiFi settings
const char* ssid = "YOUR_SSID"; // Change to your WiFi SSID
const char* password = "YOUR_PASSWORD"; // Change to your WiFi password

// WebServer settings
WebServer server(80);


// --- WAV header function prototypes ---
void writeWavHeader(File& file, int sampleRate);
void updateWavHeader(File& file);

void button_callback(){
  M5_LOGI("Start recording...");
  M5.Lcd.setCursor(0, 0);
  M5.Lcd.fillScreen(BLACK);
  M5.Lcd.println("Start recording...");
  M5.Lcd.println("Recording for "+String(PERIAD)+" seconds");
  
  File f = SPIFFS.open("/audio.wav", FILE_WRITE);
  if (f) {
    // Write WAV header
    writeWavHeader(f, SAMPLE_RATE);
    
    uint8_t buffer[CHUNK];
    size_t byte_read;
    
    // Sampling rate * 16bit * 1ch * recording time (bits)
    // /8 (bytes)
    // /CHUNK (number of chunks)
    int chunk_max = (int)((SAMPLE_RATE*16*1*PERIAD)/8/CHUNK);
    M5.Lcd.printf("Total chunks: %d\n", chunk_max);
    
    unsigned long startTime = millis();
    int progressLine = 40; // LCD position for progress
    
    for(int i=0; i < chunk_max; i++){
      M5.Mic.record(buffer, CHUNK, SAMPLE_RATE, false);
      f.write(buffer, CHUNK);
      
      // Show progress every 10 chunks
      if (i % 10 == 0) {
        M5.Lcd.setCursor(0, progressLine);
        M5.Lcd.printf("Progress: %d/%d (%.1f%%)", i, chunk_max, (float)i*100/chunk_max);
        M5.Display.print(".");
      }
    }
    
    // Get file size and update header
    updateWavHeader(f);
    f.close();
    
    unsigned long duration = (millis() - startTime) / 1000;
    M5.Lcd.setCursor(0, progressLine + 20);
    M5.Lcd.printf("Actual recording time: %lu seconds\n", duration);
    M5.Lcd.println("\nFile saved as /audio.wav");
    M5.Lcd.println("Access via: http://" + WiFi.localIP().toString());
  } else {
    M5.Lcd.println("Failed to open file for writing");
  }
  M5.Lcd.println("End recording...");
  delay(2000); // Keep the end message visible for 2 seconds
}

// Function to write WAV header
void writeWavHeader(File& file, int sampleRate) {
  byte header[44];
  unsigned int fileSize = 0;
  
  // RIFF header
  header[0] = 'R';
  header[1] = 'I';
  header[2] = 'F';
  header[3] = 'F';
  // File size (to be updated later)
  header[4] = 0;
  header[5] = 0;
  header[6] = 0;
  header[7] = 0;
  // WAVE format
  header[8] = 'W';
  header[9] = 'A';
  header[10] = 'V';
  header[11] = 'E';
  // fmt chunk
  header[12] = 'f';
  header[13] = 'm';
  header[14] = 't';
  header[15] = ' ';
  // fmt chunk size (16 bytes)
  header[16] = 16;
  header[17] = 0;
  header[18] = 0;
  header[19] = 0;
  // Audio format (1 = PCM)
  header[20] = 1;
  header[21] = 0;
  // Number of channels (1 = mono)
  header[22] = 1;
  header[23] = 0;
  // Sampling rate
  header[24] = sampleRate & 0xFF;
  header[25] = (sampleRate >> 8) & 0xFF;
  header[26] = (sampleRate >> 16) & 0xFF;
  header[27] = (sampleRate >> 24) & 0xFF;
  // Byte rate (sampling rate * channels * bytes per sample)
  unsigned int byteRate = sampleRate * 1 * 2;
  header[28] = byteRate & 0xFF;
  header[29] = (byteRate >> 8) & 0xFF;
  header[30] = (byteRate >> 16) & 0xFF;
  header[31] = (byteRate >> 24) & 0xFF;
  // Block align (channels * bytes per sample)
  header[32] = 2;
  header[33] = 0;
  // Bit depth (16 bits)
  header[34] = 16;
  header[35] = 0;
  // data chunk
  header[36] = 'd';
  header[37] = 'a';
  header[38] = 't';
  header[39] = 'a';
  // Data size (to be updated later)
  header[40] = 0;
  header[41] = 0;
  header[42] = 0;
  header[43] = 0;
  
  file.write(header, 44);
}

// Function to update WAV header with file size
void updateWavHeader(File& file) {
  unsigned int fileSize = file.size();
  unsigned int dataSize = fileSize - 44;
  
  // Move to the beginning of the file
  file.seek(0);
  
  // Update RIFF chunk size (file size - 8)
  byte fileSizeBytes[4];
  fileSizeBytes[0] = (fileSize - 8) & 0xFF;
  fileSizeBytes[1] = ((fileSize - 8) >> 8) & 0xFF;
  fileSizeBytes[2] = ((fileSize - 8) >> 16) & 0xFF;
  fileSizeBytes[3] = ((fileSize - 8) >> 24) & 0xFF;
  file.seek(4);
  file.write(fileSizeBytes, 4);
  
  // Update data chunk size
  byte dataSizeBytes[4];
  dataSizeBytes[0] = dataSize & 0xFF;
  dataSizeBytes[1] = (dataSize >> 8) & 0xFF;
  dataSizeBytes[2] = (dataSize >> 16) & 0xFF;
  dataSizeBytes[3] = (dataSize >> 24) & 0xFF;
  file.seek(40);
  file.write(dataSizeBytes, 4);
}

// Function to handle HTTP server root page
void handleRoot() {
  String html = "<html><body>";
  html += "<h1>M5Dial PDM Unit Audio Recorder</h1>";
  html += "<p>Click below to download the recorded audio:</p>";
  html += "<p><a href='/download'>Download WAV File</a></p>";
  html += "</body></html>";
  server.send(200, "text/html", html);
}

// Function to handle WAV file download
void handleDownload() {
  File file = SPIFFS.open("/audio.wav", FILE_READ);
  if (file) {
    server.sendHeader("Content-Disposition", "attachment; filename=audio.wav");
    server.sendHeader("Connection", "close");
    server.streamFile(file, "audio/wav");
    file.close();
  } else {
    server.send(404, "text/plain", "File not found");
  }
}

// Function to connect to WiFi
void connectToWiFi() {
  M5.Lcd.println("Connecting to WiFi...");
  
  WiFi.begin(ssid, password);
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 20) {
    delay(500);
    M5.Lcd.print(".");
    attempts++;
  }
  
  if (WiFi.status() == WL_CONNECTED) {
    M5.Lcd.println();
    M5.Lcd.println("WiFi connected!");
    M5.Lcd.print("IP address: ");
    M5.Lcd.println(WiFi.localIP());
    
    // mDNS setup
    if (MDNS.begin("m5dial")) {
      M5.Lcd.println("mDNS responder started");
      M5.Lcd.println("You can access at: http://m5dial.local");
    }
  } else {
    M5.Lcd.println();
    M5.Lcd.println("WiFi connection failed!");
  }
}

void setup() {
    auto cfg = M5.config();
    cfg.internal_mic = false;
    M5.begin(cfg);
    
    M5.Lcd.setBrightness(200);
    M5.Lcd.fillScreen(BLACK);
    auto mic_config = M5.Mic.config();
    mic_config.pin_ws = CONFIG_I2S_LRCK_PIN; // I2Sクロック
    mic_config.pin_data_in = CONFIG_I2S_DATA_IN_PIN; // I2S
    mic_config.sample_rate = SAMPLE_RATE; // サンプリングレート
    M5.Mic.config(mic_config);
    
    // Initialize SPIFFS
    if(!SPIFFS.begin(true)){
        M5.Lcd.println("SPIFFS Mount Failed");
        return;
    }
    
    // Connect to WiFi
    connectToWiFi();
    
    // Set up web server routes
    server.on("/", handleRoot);
    server.on("/download", handleDownload);
    
    // Start server
    server.begin();
    M5.Lcd.println("HTTP server started");
    
    M5.Lcd.println("\nPress button A to start recording");
    M5.Lcd.println("Recording time set to " + String(PERIAD) + " seconds");
}

void loop() {
  M5.update();
  if (M5.BtnA.wasClicked()) {
    button_callback();
  }
  
  // HTTPリクエストを処理
  server.handleClient();
}