Where to retrieve audio file? -- Arduino - Photon project - node.js

Question

I have just started with electronics, and doing a project using the Spark Photon, which is based on Arduino. The project website is here: http://hackster.io/middleca/sending-sound-over-the-internet
I uploaded the following two files (.ino and .js) to the Photon, which should then capture and transmit sound (directly I assume). I expected a test.wav would be created. However, where should I find this file so I can check if everything worked?
main.ino file:
#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);
// so we know where to connect, try:
// particle get MY_DEVICE_NAME ipAddress
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();
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 {
while( (val = txBuffer[i++]) < 65535 ) {
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);
}
}
and the waveRecorder.js file:
// make sure you have Node.js Installed!
// Get the IP address of your photon, and put it here:
// CLI command to get your photon's IP address
//
// particle get MY_DEVICE_NAME ipAddress
// Put your IP here!
var settings = {
ip: "192.168.0.54",
port: 3443
};
/**
* 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;
var outStream = fs.createWriteStream("test.wav");
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);

Answer 1

Thieme! Such a beginner's question... SO unworthy!
Anyway, I will iron my heart and tell you the answer.
First of all, you misunderstood: the .ino file should go to the Photon and the waveRecorder.js file should be stored on your computer (or server) and called whenever you want to retrieve the audio. As you can read in the code, the .ino file makes sure that every millisecond it will check if something wants to connect, and if so, it will stream the sound to the wav.file stored in the same location as your waveRecorder.js file. "Something wants to connect" happens when you launch waveRecorder.js. Make sure you have node installed.
So, to sum it up:
Download the two files (main.ino and waveRecorder.js) to your computer in a folder ../xx/folderName
Then configure the IPAddress in both files using your photon's IPAddress
Upload main.ino to the photon (type 'particle flash abcdefgh123456578 "xx/../folderName/main.ino"' in the terminal)
Then run waveRecorder.js by typing 'node "xx/../folderName/waveRecorder.js"' in your terminal.
That should do it.. Even I got it working :)