diff --git a/README.md b/README.md
index f3d84d2..f416183 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,14 @@ The way this works is simple (in theory, not in practice). The Arduino listens f
 
 ##board
 
-Right now, the board library will attempt to autodiscover the Arduino. I'm going to make it configurable, don't worry.
+````javascript
+var board = new arduino.Board({
+  device: "ACM"
+});
+````
+The 'device' wich arduino is attached on. 
+Here you can set the exact device (ex. ttyACM0 in my case) or the initial part of it (ex ttyACM)
+If this parameter is empty the board library will attempt to autodiscover the Arduino by quering every usb device (not the ttyACM*)
 
 ````javascript
 var board = new arduino.Board({
diff --git a/lib/board.js b/lib/board.js
index 770d4c8..55f5197 100644
--- a/lib/board.js
+++ b/lib/board.js
@@ -12,6 +12,7 @@ var events = require('events'),
 var Board = function (options) {
   this.log('info', 'initializing');
   this.debug = options && options.debug || false;
+  this.device = options && options.device || 'usb';
   this.writeBuffer = [];
 
   var self = this;
@@ -71,7 +72,7 @@ util.inherits(Board, events.EventEmitter);
 Board.prototype.detect = function (callback) {
   this.log('info', 'attempting to find Arduino board');
   var self = this;
-  child.exec('ls /dev | grep usb', function(err, stdout, stderr){
+  child.exec('ls /dev | grep '+ this.device, function(err, stdout, stderr){
     var usb = stdout.slice(0, -1).split('\n'),
         found = false,
         err = null,