QR code (http://en.wikipedia.org/wiki/QR_Code) is a 2D bar code used to encode fair amount of data in a sort of 2D bar code. This code can then be read by cell phones or barcode readers. My choice is for QR Code as it is one of the most used and a simple encoder / decoder for PC and mobile phones is readily available for free.
Another code is Data Matrix (http://en.wikipedia.org/wiki/Data_Matrix) which is now having some backup from both the US Govt and the electronic industry which is planning to add extra information on top of chips and small components: these would be read by automatic assembly machines for a more reliable and foolproof assembly of boards.
PC and mobile phones encoders/decoders are available for Datamatrix as well, but I went for QR code and basta ! No, actually I tried some free Datamatrix decoders and proved less reliable, on my phone at lest, than the QR decoder I am showing here.
"QR Code is trademarked by Denso Wave, inc. as stated in Denso Wave's" this is what can be read on Wikipedia and on Denso Wave's homesite but we can read also that (http://www.denso-wave.com/qrcode/microqr-e.html) "QR Code is open in the sense that the specification of QR Code is disclosed and that the patent right owned by Denso Wave is not exercised.".

And that's great because this opens to a great deal of opportunities.

...Follow me then and you'll have Y2010 business cards also.

Note (01/02/08) :
Jaxo System's web address has moved to http://www.jaxo-systems.com (thank you, jackOjack)

Step 1: Parts needed

You'll need the following:

Some text to 2D-encode (and worth to decode !).
A PC with a Web browser and Java VM : Windows or Linux doesn't matter for the encoding process.
The decoder applet for your camera-equipped mobile (if you want to decode also, I want).

The text for me will be http://www.instructables.com and http://www.5volt.eu , the latter being the place where I post my projects I can't make an Instructable. Both worth to me to encode and print on stickers, business cards and T-shirts.

The PC can be any, equipped with a web browser and Java.
Jaxo Systems ( http://www.jaxo-systems.com/home ) makes software for image processing also and provide decoding Java applications for mobile phones and PCs to acquire and decode various bar codes (2D included) and free to download.
In their homepage you can encode your text and save the 2D representation as a graphic file ready for print.
You can also download the jar file to execute as a stand alone application.

Use is granted by Jaxo Systems for personal use only, as stated in their homepage.

Below is a roundup of addresses found by readers and posted in comments.
Many of them have downloads for mobile phones, some others have directions for others sites also.

http://www.drhu.org/ (suffering HD failure as of 31/01/08)
<p>I downloaded the <a href="http://www.businessrefinery.com/products/barcode_reader_java/main.html" rel="nofollow">2D barcode decoder</a> and successfully encoded the barcode on my business cards.It's very helpful.</p>
cool, but you know what, I got a tattoo of <a href="http://www.barcodelib.com/barcode_software/qrcode.html" rel="nofollow">barcode</a> on my head. Besides, can I use some other colors, you know I can not always wear a white T-shirt.
This is a great instructable! Here is one for you all:
never laughed so hard looking at my phone
Never ask a naked man to point north!
That's cool! I've heard about it before and would like to have a try~<br>This is a comprehensive barcode professional website (http://www.onbarcode.com/) and I used it a lot.<br>Complete barcode solutions for .NET, Java, and Smartphones are provided here. Easy and efficient to use, so try them at following web sites.<br>http://www.onbarcode.com/software/barcode_generator.html<br>http://www.onbarcode.com/products/net_barcode/<br>http://www.onbarcode.com/products/java_barcode/
mobosurvey says: With <a href="http://www.mobosurvey.com" rel="nofollow">http://www.mobosurvey.com</a> you can create forms/surveys and distribute through QR code. The forms/surveys will have the native look and feel to your visitor's device (mobile, desktop, or tablet).
My brother makes custom furniture / art deco pieces, and tags them with QR. As the piece sits in someone's lobby or other such place, if someone is interested in it, they scan the QR, it takes them directly to the webpage for that particular one, and they can purchase it via paypal, right from their phone! The site also allows them to contact him, or browse other pieces of furniture / art. Your point of using it at historical landmarks is something I was just thinking about a few days ago, prior to reading this. A local community is looking into some more &quot;interactive&quot; things, and my suggestion would be to use these things for a &quot;walking tour&quot; type of situation.
You can print qr to cafe press
brilliant stuff!. The list of scanners is pretty good even though there are a good more out there. Google has its own project (java and objective C) scanner if any ones looking - 'zxing project' - just do a google search.<br> <br> Sticking to the theme of this page...I think there are a great more uses which havent yet been spoken of in the forum,<br> <br> Ive stumbled across a site which has many more ways to encode data into the 2d barcode. The <a href="http://www.m0b1le.net/index.php?template=2d-barcode-business-card">2d barcode business card</a>&nbsp;is there but they also have a <a href="http://www.m0b1le.net/index.php?template=2d-barcode-map">2d barcode map</a>&nbsp;which someone plugged into google maps! you can find a location which stores itself in the qr code, then when scanned it opens up the mapping software on your phone too and asks if you want directions. &nbsp;There's the standard <a href="http://www.m0b1le.net/index.php?template=2d-barcode">2d barcode</a> which can store data, and of course the <a href="http://www.m0b1le.net/index.php?template=2d-barcode-sms">2d barcode sms</a>! - when I used the site it was all free of charge!<br> <br> I think these 2d barcodes are fantastic! and Rumour has it we will see huge uptake with them next year!<br> <br> Happy creating! and scanning everyone.
<p>Here&rsquo;s another approach that's focused on sharing your social networks + be able to edit it in the future + see the analytics!</p> <p><a href="http://getsharesquare.com/" rel="nofollow">http://getsharesquare.com/</a></p> <p>Here&rsquo;s mine: <a href="http://shrsqr.com/ABCDE" rel="nofollow">http://shrsqr.com/ABCDE</a></p> <p>Tip: if you add a plus sign to the above URL you can see some cool analytics!</p>
nice! now I just need a laser scanner...&nbsp;
I have seen this concept used in 3D. the patch is still 2D but if you send it through a program it pops out as a 3D image. If you rotate the patch the image rotates to show its side.<br />
Jaxo seems to work great for me. Check out my "Business Code".
Before you put that on a business card you should consider using the &quot;Contact Info&quot; data type for the QR code. You've got the information in plain text, but some phones/readers, such as the Android phone, can parse QR data as a contact and import it into the phone book with the appropriate fields already filled in.&nbsp; Here's a page I use:<br /> <br /> http://zxing.appspot.com/generator/<br /> <a href="http://www.instructables.com/id/QR-Code-Cross-Stitch-Patch/" rel="nofollow"><br /> The Cross Stitch Instructable</a> uses the Contact Info format, so you can check out that page with your phone to see if it detects the difference.<br /> <br /> In the drop down box, the second entry is &quot;Contact information&quot; and &quot;Text&quot; is second to last.&nbsp; Other standard data types that can be generated with that page are: Calendar event, Email address, Geo location, Phone number, SMS, and URL.<br /> <br /> QR Code also has support for Japanese characters.&nbsp; Unfortunately,QR codes just have a fairly stand ASCII alphabet and a decent Japanese alphabet, but no other character sets or unicode, as it was only designed for those languages.&nbsp; I'm willing to bet if QR Codes catch on, a unicode datatype will be created.<br />
Daniel Wright<br/>Freelance Photographer<br/>Photo-Worx<br/><a rel="nofollow" href="http://www.photo-worx.com">http://www.photo-worx.com</a><br/>info@photo-worx.com<br/>(920) 598-0956<br/>
Thats naughty....
what is it
Hi I've tested this decoder, I'm thinking how it may work. I tested it on 3 different cell phones including Java mobile client...no way even to install 2 of them (BBerry + HTC). On the N6280 the installation is ok but, unfortunately, I wasn't able to read any QR barcode (except the huge ones) and it takes time to decode. Is someone making the same experience or am I wrong somewhere ?
If you have an android phone (most new HTC and some others) Google Goggles can read qR<br />
This is Awesome! And Easy Too! I cant wait to put codes all over the place!
This is super sweet, now I can have t shirts of all my favorite pick up lines such as
5a"If I said you had a beautiful body would you take your pants off and dance around a bit?"
yes lol
Does your pickup line work ? LOL
Only on my wife.
I'm surprised it works on her
I could try but I'm not very good at dancing!
Also this works fine on my K750i just to let you know.
OK, excellent. Thank you.
It doesn't support treo's =[<br/>
can you help my nokia 6103 wont work!
Hey guys, pull out your decoder applets!
14Drink your ovaltine?
Yep, minus the 14.
wasn't it "be sure to drink your ovaltine" if your quoting the same movie I'm thinking of
"remember to set your decoder rings to B2" was it B2 or B12? i can't remember
maybe, but i haven't seen it in a long while, so who knows?(...wikipedia...)

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