add better arduino error handling

Server won't just crash when no arduino is available.

nodejs/routes/index.js

@@ -1,17 +1,22 @@
 var express = require('express');
 var router = express.Router();
+var sucess = true;
 var SerialPort = require("serialport").SerialPort
-var serialPort = new SerialPort("/dev/ttyACM0", {
+serialPort = new SerialPort("/dev/ttyACM0", {
   baudrate: 9600
-});
+}, false).open(function (error) {
+            if ( error ) {
+              sucess = false;
+            }
+          });
 
-/* GET home page. */
+/* GET home page. */ 
 router.get('/', function(req, res, next) {
   res.render('index', { title: 'Express' });
 });
 
 router.get('/toggleLight', function (req, res) {
-  serialPort.write(new Buffer('~','ascii'));
+  if(sucess) { serialPort.write(new Buffer('~','ascii')); } else {console.log("arduino not connected")}
   res.send('switch light');
 });