An excellent article by Alun Anderson, Editor in Chief of New Scientist
Back in 1965 Gordon Moore laid out his famous law that the number of components that could be squeezed on to a silicon chip would double every year or two...
Moores law still has a long future. But in 2004 the belief that progress means packing in ever more computing power will be seen as far too narrow.
Just arriving is another kind of information revolution, driven by the ability to manufacture billions of tiny, intelligent communicating sensors. Capable of organising themselves into networks, intelligent sensors will make up for their small brains by their immense numbers...
Enter Smart Dust: computers so small that you would not notice if one floated in through your window on the breeze ... [offering] limited sensors, intelligence and communication abilities, but in vast numbers...
Smart-dust advocates have visions of sending billions of these machines into the atmosphere so that the entire planet could be wired. Stupendous networks of communicating sensors would give the earth a digital nervous system accessible to the web and giant search engines, from which we could instantly access anything about the state of the planet, from changing weather to the state of forests.
And here is Rafe Needleman, writing in Business 2.0, February 13, 2003
The motes have radios in them to communicate their sensor readings. This is where things get really interesting. The low-power radios attached to these low-power computers don't have enough range to continuously broadcast back to a central base station. Instead, they wake up once in a while, at predetermined times, and blast their data to a nearby mote, which then collects and retransmits that data to another nearby mote, and so on, until finally the data reaches a central collection node or recording computer.
This is what's known as a self-organizing sensor network, and it's a powerful idea. One obvious application is military: Air-drop a bunch of vibration sensors into the Iraqi desert and they can report vehicle and personnel movement. A similar technique could be used to gather data on seismic activity or monitor highway traffic.
Mesh networking isn't a brand-new idea. And likewise, small computers and sensors are hardly innovative. But combining small sensors, low-power computers, and mesh radios in the manner I've just described makes for a new technological platform that already has important uses and applications.
Nice graphics from The Economist, World In 2004 show the shrinking size of nano-processors.