Photon Audio Example

main.ino

#define MICROPHONE_PIN A5
#define AUDIO_BUFFER_MAX 8192

int audioStartIdx = 0, audioEndIdx = 0;
uint16_t audioBuffer[AUDIO_BUFFER_MAX];
uint16_t txBuffer[AUDIO_BUFFER_MAX];

// version without timers
unsigned long lastRead = micros();
char myIpAddress[24];

TCPClient audioClient;
TCPClient checkClient;
TCPServer audioServer = TCPServer(3443);

void setup() {
    Serial.begin(115200);
    pinMode(MICROPHONE_PIN, INPUT);
    
    // This lines look up your Particle's local IP Address and make it available via 
    // `particle get  MY_DEVICE_NAME ipAddress` from the CLI.
    Spark.variable("ipAddress", myIpAddress, STRING);
    IPAddress myIp = WiFi.localIP();
    sprintf(myIpAddress, "%d.%d.%d.%d", myIp[0], myIp[1], myIp[2], myIp[3]);
    
    // 1/8000th of a second is 125 microseconds
    audioServer.begin();

    // EDIT: This will print your local IP Address to Serial Monitor of a USB-attached computer (can be accessed through Arduino IDE)
    Serial.println("local IP Address");
    Serial.println(myIpAddress);

    lastRead = micros();
}

void loop() {
    checkClient = audioServer.available();
    if (checkClient.connected()) {
        audioClient = checkClient; 
    }
    
    //listen for 100ms, taking a sample every 125us,
    //and then send that chunk over the network.
    listenAndSend(100);
}

void listenAndSend(int delay) {
    unsigned long startedListening = millis();
    
    while ((millis() - startedListening) < delay) {
        unsigned long time = micros();
        
        if (lastRead > time) {
            // time wrapped?
            //lets just skip a beat for now, whatever.
            lastRead = time;
        }
        
        //125 microseconds is 1/8000th of a second
        if ((time - lastRead) > 125) {
            lastRead = time;
            readMic();
        }
    }
    sendAudio();
}

 
// Callback for Timer 1
void readMic(void) {
    uint16_t value = analogRead(MICROPHONE_PIN);
    if (audioEndIdx >= AUDIO_BUFFER_MAX) {
        audioEndIdx = 0;
    }
    audioBuffer[audioEndIdx++] = value;
}

void copyAudio(uint16_t *bufferPtr) {
    //if end is after start, read from start->end
    //if end is before start, then we wrapped, read from start->max, 0->end
    
    int endSnapshotIdx = audioEndIdx;
    bool wrapped = endSnapshotIdx < audioStartIdx;
    int endIdx = (wrapped) ? AUDIO_BUFFER_MAX : endSnapshotIdx;
    int c = 0;
    
    for(int i=audioStartIdx;i<endIdx;i++) {
        // do a thing
        bufferPtr[c++] = audioBuffer[i];
    }
    
    if (wrapped) {
        //we have extra
        for(int i=0;i<endSnapshotIdx;i++) {
            // do more of a thing.
            bufferPtr[c++] = audioBuffer[i];
        }
    }
    
    //and we're done.
    audioStartIdx = audioEndIdx;
    
    if (c < AUDIO_BUFFER_MAX) {
        bufferPtr[c] = -1;
    }
}

// Callback for Timer 1
void sendAudio(void) {
    copyAudio(txBuffer);
    
    int i=0;
    uint16_t val = 0;
        
    if (audioClient.connected()) {
       write_socket(audioClient, txBuffer);
    }
    else {
        // will only run if there's no script listening for audio
        while( (val = txBuffer[i++]) < 65535 ) {
            // this will generate a lot of output; comment out if you just want the IP address
            Serial.print(val);
            Serial.print(',');
        }
        Serial.println("DONE");
    }
}


// an audio sample is 16bit, we need to convert it to bytes for sending over the network
void write_socket(TCPClient socket, uint16_t *buffer) {
    int i=0;
    uint16_t val = 0;
    
    int tcpIdx = 0;
    uint8_t tcpBuffer[1024];
    
    while( (val = buffer[i++]) < 65535 ) {
        if ((tcpIdx+1) >= 1024) {
            socket.write(tcpBuffer, tcpIdx);
            tcpIdx = 0;
        }
        
        tcpBuffer[tcpIdx] = val & 0xff;
        tcpBuffer[tcpIdx+1] = (val >> 8);
        tcpIdx += 2;
    }
    
    // any leftovers?
    if (tcpIdx > 0) {
        socket.write(tcpBuffer, tcpIdx);
    }
}
    

waveRecorder.js

// make sure you have Node.js Installed!
// make sure you first run `npm install particle-api-js`

// Type in your local IP here! Or scroll down and get the script to find it on
//your behalf (comment out the next 4 lines if you go for this option).
var settings = {
    ip: "YOUR_IP_ADDRESS",
    port: 3443
};

var Particle = require('particle-api-js');
var particle = new Particle();
var token = 'YOUR_TOKEN_HERE'; // Find your token under "Settings" at https://build.particle.io/

// EDIT: Connects to Particle Photon and saves token if you dont want to look it up
//particle.login({username: 'youraccountname@email.com', password: 'yourpassword'}).then(function(data){
//
//  console.log('Logged in');
//  token = data.body.access_token;
//
//});

// EDIT: Another way to ask the Particle for its Local IP Address
particle.getVariable({ deviceId: 'YOUR_DEVICE_NAME', name: 'ipAddress', auth: token })
        .then(function(data) {

          console.log("IP address: ", data);
          settings.ip = data.body.result;

          /**
           * Created by middleca on 7/18/15.
           */

          //based on a sample from here
          //  http://stackoverflow.com/questions/19548755/nodejs-write-binary-data-into-writablestream-with-buffer

          var fs = require("fs");

          var samplesLength = 1000;
          var sampleRate = 8000;

          // EDIT: New additions - turns "test.wav" in "fs.createWriteStream("test.wav");""
          // into a variable that gets current time and date
          var d = new Date();
          var outStream = fs.createWriteStream("Record--"+d.toString().split(' ').join('-')+".wav");

          // EDIT: Writes the beginning of the WAV file
          var writeHeader = function() {
              var b = new Buffer(1024);
              b.write('RIFF', 0);
              /* file length */
              b.writeUInt32LE(32 + samplesLength * 2, 4);
              //b.writeUint32LE(0, 4);

              b.write('WAVE', 8);
              /* format chunk identifier */
              b.write('fmt ', 12);

              /* format chunk length */
              b.writeUInt32LE(16, 16);

              /* sample format (raw) */
              b.writeUInt16LE(1, 20);

              /* channel count */
              b.writeUInt16LE(1, 22);

              /* sample rate */
              b.writeUInt32LE(sampleRate, 24);

              /* byte rate (sample rate * block align) */
              b.writeUInt32LE(sampleRate * 2, 28);

              /* block align (channel count * bytes per sample) */
              b.writeUInt16LE(2, 32);

              /* bits per sample */
              b.writeUInt16LE(16, 34);

              /* data chunk identifier */
              b.write('data', 36);

              /* data chunk length */
              //b.writeUInt32LE(40, samplesLength * 2);
              b.writeUInt32LE(0, 40);


              outStream.write(b.slice(0, 50));
          };


          writeHeader(outStream);


          var net = require('net');
          console.log("connecting...");
          client = net.connect(settings.port, settings.ip, function () {
              client.setNoDelay(true);

              client.on("data", function (data) {
                  try {
                      console.log("GOT DATA");
                      outStream.write(data);
                      //outStream.flush();
                      console.log("got chunk of " + data.toString('hex'));
                  }
                  catch (ex) {
                      console.error("Er!" + ex);
                  }
              });
          });




          setTimeout(function() {
              console.log('recorded for 10 seconds');
              client.end();
              outStream.end();
              process.exit(0);
          }, 10 * 1000);

});