A simple Meshblu connector to play base64 encoded mp3 and drive a Big Mouth Billy Bass motors.

piaudio.js

// Put a meshblu.json file in the same directory as this file. This must
// contain the Meshlu device UUID and token, e.g.:
// {"server":"meshblu.octoblu.com","port":80,"uuid":"01234567-89ab-cdef-0123-456789abcdef","token":"123456789012345678901234567890"}


var meshblu = require('meshblu');
var meshbluJSON = require("./meshblu.json");
var exec = require('child_process').exec;
var tempfile = require('tempfile');
var fs = require('fs');
var SerialPort = require("serialport");

// Specifies how you want your message payload to be passed
// from Octoblu to your device
var MESSAGE_SCHEMA = {
  type: 'object',
  properties: {
    mp3: {
      type: 'string',
      required: true
    }
  }
};

var portdev = "/dev/ttyACM0";
var port = new SerialPort(portdev, {
  baudRate: 9600,
  parser: SerialPort.parsers.readline('\n')
});

port.on('error', function(err) {
  console.log('Error: ', err.message);
})

port.on('data', function (data) {
  console.log('Data: ' + data);
  conn.message({
    "devices": "*",
    "command": data
  });
});

// We'll process messages sequentially - build a queue
function MyController() {
  this.timeout = 100;
  this.queue = [];
  this.ready = true;
};

MyController.prototype.exec = function() {
  this.queue.push(arguments);
  this.process();
};

MyController.prototype.action = function(message) {
  var self = this;
  console.log("Processing message...");
  if ('mp3' in message) {
    var mp3file = tempfile(".mp3");
    port.write("HEAD MOVE\n");
    fs.writeFile(mp3file, new Buffer(message.mp3, "base64"), function(err) {
      if (err) {
        console.log("Error writing temporary MP3 file: " + err);
        fs.unlinkSync(mp3file);
        port.write("HEAD RELEASE\n");
        self.ready = true;
        self.process();
      }
      else {
        exec("omxplayer " + mp3file, function(err, stdout, stderr) {
          console.log('stdout: ' + stdout);
          console.log('stderr: ' + stderr);
          if (err !== null) {
            console.log('exec error: ' + err);
          }
          port.write("TAIL MOVE\n");
          setTimeout(function() {
            port.write("TAIL RELEASE\n");
          }, 500);
          setTimeout(function() {
            self.ready = true;
            self.process();
          }, 1500);
        });
      }
    });
  }
};

MyController.prototype.process = function() {
  if (this.queue.length === 0) return;
  if (!this.ready) return;
  var self = this;
  this.ready = false;
  this.action.apply(this, this.queue.shift());
};

var messageController = new MyController();

// Not specifying a UUID/Token auto-registers a new device
var conn = meshblu.createConnection({
  "uuid": meshbluJSON.uuid,
  "token": meshbluJSON.token,
  "server": "meshblu.octoblu.com",
  "port": 80
});

conn.on('notReady', function(data){
  console.log('Octoblu UUID FAILED AUTHENTICATION!');
  console.log(data);
});

conn.on('ready', function(rdata){
  console.log('UUID AUTHENTICATED!');
  console.log(rdata);

  conn.update({
    "uuid": meshbluJSON.uuid,
    "token": meshbluJSON.token,
    "messageSchema": MESSAGE_SCHEMA,
  });

  conn.on('message', function(data){
    console.log('Octoblu message received');
    //console.log(data);

    messageController.exec(data);
  });
});