Simple Azure IoT client to relay messages to an Arduino via serial-over-USB

xmas.js

var SerialPort = require("serialport");
var clientFromConnectionString = require('azure-iot-device-amqp').clientFromConnectionString;
var tinycolor2 = require("tinycolor2");

var connectionString = "<IoT Hub connection string>";

var portdev = "/dev/ttyACM0";
var port = new SerialPort(portdev, {
  baudRate: 9600,
});

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

port.on('data', function (data) {
  console.log('Data: ' + data);
});

// AMQP-specific factory function returns Client object from core package
var client = clientFromConnectionString(connectionString);

// use Message object from core package
var Message = require('azure-iot-device').Message;

var connectCallback = function (err) {
  if (err) {
    console.error('Could not connect: ' + err);
  } else {
    console.log('Client connected');

    client.on('message', function (msg) {
      console.log('Id: ' + msg.messageId + ' Body: ' + msg.data);

      if (msg.data.toString() == "flash") {
        port.write("FLASH\n");
      } else if (msg.data.toString() == "noflash") {
        port.write("NOFLASH\n");
      }
      else  {
        var c = tinycolor2(msg.data.toString()).toRgb();
        // Divide all values by 4 to reduce brightness and power usage
        var r = c.r / 4;
        var g = c.g / 4;
        var b = c.b / 4;
        console.log(r,g,b);
        // These LEDs have red and green swapped
        var x = "COLOR " + tinycolor2({ r: g, g: r, b: b }).toHexString() + "\n";
        port.write(x);
        console.log(x);
      }

      client.complete(msg, printResultFor('completed'));
    });
  };
};

client.open(connectCallback);

// Helper function to print results in the console
function printResultFor(op) {
  return function printResult(err, res) {
    if (err) console.log(op + ' error: ' + err.toString());
    if (res) console.log(op + ' status: ' + res.constructor.name);
  };
}