QR codes? I’m thinking this is something to do with barcodes…
And you’d be right. A QR code is a 2D matrix barcode which uses an arrangement of squares to encode information horizontally and vertically. Using two dimensions mean a QR code can contain more information than its common cousin, the linear barcode, which earns a crust at the supermarket checkout.

And because 2D barcodes can embed more information they have the potential to be used for more sophisticated applications than mere item-level tagging.

Such as?
To store and point to a whole URL say – or to contain full contact details on a business card. However it’s not the particular data stored in QR codes that makes them special per se, it’s the notion of being able to gain fast on-the-fly access to that data. So combine QR codes with mobile phones and you have the potential for a world with a QR code reader in every pocket…

That does sound interesting. Is the QR code the only 2D barcode out there then?
No. There are lots of 2D barcodes (see below for an example of another type) but the QR code is the most high profile. Mostly because it’s so big in Japan where it’s widely used in conjunction with cameraphones as a snappy way of accessing info on a phone. QR stands for ‘quick response’, you know.

QR codes were invented in 1994 by a Japanese company called Denso-Wave, for tracking car parts. Now Denso allows anyone – or any organisation – to use QR codes free of charge. In fact the company does a line in 2D barcode scanning hardware and software so is clearly happy for everyone and their dog to be consuming QR codes. It’s not in the mobile phone business though – and it’s mobiles that have brought QR codes to mainstream attention.

Enough of the history already. Can I get my phone to scan these QR codes then?
Well you need a cameraphone with QR code reading software on it. Some phones have barcode scanning software pre-loaded (again, much more likely if you live in Japan, but Nokia has also shown an interest in barcode readers so it’s worth checking out what your model has to offer) but there are software apps available for download on the internet. However, not all phones are compatible with these apps – so be prepared to be disappointed.

If you’re lucky enough to have a ‘QR-capable’ phone, then it’s just a case of spotting a code – say, printed in a newspaper or on a billboard – firing up the scanner app and pointing your cameraphone at the pixelated square. The reader software will scan the code and crunch the data.

If the QR code contains a URL you should automatically be taken to that website on your phone (which surely beats typing in long URLs). Or you may find a text message has been encoded in the matrix…

Sounds very futuristic. Where would I find a QR code then?
Well that depends where you are. If you live in Japan, you’ll probably see 100 before breakfast (printed on food items, stickers, posters, clothing etc) but they are no way near as common in Blighty. However, at least one UK newspaper has just started printing QR codes on its pages to point its readers to the latest news.

You can see an example of a QR code here – note the identifying mark of smaller squares in the corners.

A cursory search on flickr shows up some interesting – and outlandish – deployments of QR codes, such as T-shirts and even a pair of oversized earrings.

Out and about in London, I spotted this two-dimensional barcode (see below) – screwed to a billboard outside a club in Vauxhall. It is not a QR code but another type of 2D code, called a Data Matrix, which stores fewer characters:

So how many characters can a QR code store?
According to Denso, a typical QR code can store 7,089 numeric characters or 4,296 alphanumeric characters (a bit less than this Cheat Sheet), or 2,953 binary characters. The company also notes that 1,817 Kanji characters can be stored – back to those Japanese roots again.

Hm, so what’s the catch? Why aren’t we all snapping QR codes off our breakfast cereal with our ubiquitous cameraphones?
In Western European mobile markets at least this is very much an emerging tech so getting your mobile to read a QR code is not necessarily that easy. Some BlackBerrys, for instance, are not compatible with QR reader software. And getting the reader apps to work on phones that are apparently compatible is not always straightforward. Such software has to work with the many different OSes out there – and different mobile models need to be tested individually so there’s apparently no quick win.

You also ideally need ubiquitous high-speed mobile internet – to retrieve the data stored in the QR code – and in Europe such connectivity has taken longer than many hoped to get off the ground (again, it’s been bigger for far longer out East). But with the rise of the HSDPA world, however, conditions could be ripening for our own QR code revolution.

Are there any alternatives to QR codes?
There could be. If everyone had NFC phones, for instance, then RFID-style Topaz tags could be used instead of QR codes, with mobiles retrieving data stored on the tags. Of course cameraphones are far more common than near field communication phones right now, so QR codes have a bit of a head start.

And even if NFC chips are cheap, paper is surely cheaper…