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Arduino, Flex 3 and XMLSocket class

29 November 2009 2 Comments

As Adobe Developer I’m trying a lot of solutions to control external devices from my Flash, Flex and AIR applications but using Arduino Microcontroller (my favourite one in this period ; ) I got some issues and limitations.

In this article I have extended the ActionScript 3.0 XML Socket Class to send messages from Flex 3 to Arduino and viceversa and even if it works well for simple stuff it seems far from the final solution.

Naturally I have already tested Firmata 2.0, AS3 Glue Library and other stuff I have found around the web (you can read something about this topic in this article I wrote) but they have big limits with Servo and I think they are not ready to use in combination with LCD, Bluetooth, GPS and so on. I only used them to turn on/off digital and analog pins.

It’s nice but I was thinking about a custom solution. Probably it won’t be flexible like a standard library but enough for me to accomplish all the tasks I need.

So, this simple Flex application (usable on Flash CS3/4 too) allows me to turn On/Off two Leds too, connected to pin 2 and 13 but if you read the whole article you will know that i’m not so happy about this solution.

I hope to get inspiration from this and you will help me to get new ideas (please write me in private emails or post a comment).

This is the actionscript 3.0 class:

package arduino{
    import flash.display.Sprite;
    import flash.events.*;
    import flash.net.XMLSocket;
 
    public class FBXMLArduino extends Sprite {
 
        private var hostName:String = "127.0.0.1";
        private var port:uint = 5335;
        private var socket:XMLSocket;
 
        public function FBXMLArduino() {
            socket = new XMLSocket();
            configureListeners(socket);
            if (hostName && port) {
                socket.connect(hostName, port);
            }
        }
 
        public function send(data:Object):void {
            socket.send(data);
        }
 
        private function configureListeners(dispatcher:IEventDispatcher):void {
            dispatcher.addEventListener(Event.CLOSE, closeHandler);
            dispatcher.addEventListener(Event.CONNECT, connectHandler);
            dispatcher.addEventListener(DataEvent.DATA, dataHandler);
            dispatcher.addEventListener(IOErrorEvent.IO_ERROR, ioErrorHandler);
            dispatcher.addEventListener(ProgressEvent.PROGRESS, progressHandler);
            dispatcher.addEventListener(SecurityErrorEvent.SECURITY_ERROR, securityErrorHandler);
        }
 
		private function dataHandler(event:DataEvent):void {
            trace("From Arduino --->: " + event.data);
        }
 
        private function closeHandler(event:Event):void {
            trace("closeHandler: " + event);
        }
 
        private function connectHandler(event:Event):void {
            trace("connectHandler: " + event);
        }
 
 
        private function ioErrorHandler(event:IOErrorEvent):void {
            trace("ioErrorHandler: " + event);
        }
 
        private function progressHandler(event:ProgressEvent):void {
            trace("progressHandler loaded:" + event.bytesLoaded + " total: " + event.bytesTotal);
        }
 
        private function securityErrorHandler(event:SecurityErrorEvent):void {
            trace("securityErrorHandler: " + event);
        }
    }
}

This is the Flex MXML Application file:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical"
	creationComplete="init()">
 
 
	<mx:Script>
		<![CDATA[
			import arduino.FBXMLArduino;
 
			private var socket:FBXMLArduino;
 
			private function init():void {
 
				socket = new FBXMLArduino();
 
			}
		]]>
	</mx:Script>
 
 
	<mx:Button label="Disable LEDS" click="socket.send(1);" />
	<mx:Button label="Turn On LED 2" click="socket.send(2);" />
	<mx:Button label="Turn On LED 13" click="socket.send(3);" />
</mx:Application>

Following the Arduino Sketch:

char message ;
 
void setup(){
   Serial.begin(9600);  //setup serial conversation at 19200 bauds
   pinMode(2, OUTPUT);      // sets the digital pins 2 as output
}
 
 
void loop () {
 
 // checks if a serial message has arrived to the board
  if(Serial.available()) {      
 
	// Get data from Flex
        message = Serial.read();
 
         // Check ASCII TABLE
        // http://web.cs.mun.ca/~michael/c/ascii-table.html
         switch(message) {
            // Digit 2
            case 50:
               digitalWrite(2, HIGH); 
 
	       // send this sentence to Flex
	       Serial.println("Turn On LED2"); 
              break;
 
            // Digit 3     
            case 51:
               digitalWrite(13, HIGH); 
              break;
            case 49:
               digitalWrite(2, LOW); 
               digitalWrite(13, LOW); 
              break;
 
         } 
 
   }  
 
 
 delay(150);
 
}

NOTE: remember that you need to use a serial proxy application to allow communication between Arduino and Flash.
You can get more info about it on Arduino or in the AS3 glue official web sites.

CONSIDERATIONS:

This script works well but following some considerations:

1) To get results in the Arduino code, I would like to use decimal values and not ascii code but i’m not able to make a comparison like:
if (message == 2) and i have to use its ascii value (50). Suggestions?

2) If i send a number > 9 or a string with more than 2 chars I’m not able to get an intere value but it’s splitted.
For example, if i send 134 i will get “1″, after 150ms, “2″ and after 300ms the last value, “3″ so I’m not able to get 134.

Naturally I think there could be workarounds to merge these values but I also think there could be best way to do it.
I’m not so inside electronic stuff and neither inside C language.
So i have shared this script hoping that somebody will give me some suggestions.