Features

Kindberg feels there is a future for both RFID and barcodes. "They involve little user effort. Mobile phone readers are available in both cases, so there can be billions of readers in users' hands. The costs of the tags themselves are low, so we can have the necessary trillions of tags. Barcodes have great advantages over RFID. They cost almost zero, just a little ink. And they can be read by existing camera phones, so there's no new hardware. RFID tags will always cost more than barcodes. And new hardware is needed on the handset. But RFID tags can in principle be read more robustly because there's no dependency on reasonable lighting conditions, and they can be made robust against environmental rigours - my dog has one in his neck."

Hope and glory

A couple of projects completed by the Active Print project give a glimpse into the future. In 2005, the Bristol-based record company Hope Recordings used Active Print technology to promote a compilation album Seven Year Itch. QR codes appeared on posters for the album as well as in adverts in magazines. By pointing their phones at the posters or advertisements, fans could download videos and music clips to get a taste of the album.

At the same time, the popular BBC Coast series used similar technology to guide viewers on a series of coastal walks. At each point along the walks there was a BBC Coast sign containing a Data Matrix code (a 2D barcode that is similar to the QR code) and instructions

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on how to use it. On arriving at a sign, hikers pointed their mobile phone's camera at the Data Matrix code and, within seconds, multimedia content appeared on the screen explaining the significance of the current location and giving directions to the next stop on the route.

Geographical tagging

All the methods we've seen so far for tagging real-world objects are suitable for things that can move around. If something is rooted to the spot, however, there's an alternative way of giving it a place on the internet. Buildings, mountains, rivers and the like can be identified purely from their geographical location and there are a number of ways of accessing that information automatically.

For super-accurate positioning there's satellite-based GPS, which forms the basis of navigation systems. GPS adaptors are available for notebooks and PDAs and even some 3G mobile phones now have built-in GPS circuitry that can give a position, accurate to a few metres, anywhere in the world.

For a somewhat less accurate position, any mobile phone can work out its approximate location from knowledge of the base station (mast) it's connected to and how strong the signal is from that base station. Mobile phone companies and third parties are already exploiting this capability by providing location-based services. With the advent of assisted GPS (see page 130) providing an easier and faster way to use GPS, this could be an important step towards the Internet of Things.

At the moment, the most common use of location-based services is to allow people to find businesses in an area they are unfamiliar with. The 'where's my nearest?' service that's offered by many of the network operators lets you ask for the name, address and telephone number of the nearest hotel, Chinese restaurant or petrol station, for example. In London, the Zingo taxi-hailing service puts you in contact with the driver of the closest black cab. Location-based games such as Geocaching, which is essentially a high-tech treasure hunt, have also gained a cult following.