While sitting in an iCORE/Xerox Research Chair meeting today, Qingsheng Zhang gave a presentation which discussed various kinds of tag, with a particular emphasis on those that can be attached to physical objects. It occurred to me that it would be a nice idea to use sonic tags - essentially, a small strip that would have a raised (or embossed) pattern of lines, that you could 'read' by scratching across the lines with your fingernail. It's much the same concept as melody roads in Japan (http://www.guardian.co.uk/world/2007/nov/13/japan.gadgets) where differently spaced road markings perform much the same role.

In fact, taking the concept a bit further, you could probably use existing 1D bar codes to produce sufficiently different sounds to distinguish any object from another.

Why bother? They're really easy to create, really cheap to manufacture, there's plenty of software available to decode and deal with 1D barcodes, and every cellphone in the world could read them.

I wonder if it has already been done? Is it possible? It does seem an obvious but very useful idea.