Long ago I wrote the article How Motes Work. It is about a technology also known as smart dust. The idea is that there can be very small, computerized sensors that intercommunicate with each other to gather information about the world.
This video gives you a nice introduction to the smart dust concept:
The following video shows a potential application of smart dust:
The military also sees lots of applications.
According to this article, we are getting closer to seeing this kind of technology for real:
The latest news comes from the computer and printing company Hewlett-Packard, which recently announced it's working on a project it calls the "Central Nervous System for the Earth." In coming years, the company plans to deploy a trillion sensors all over the planet.
The wireless devices would check to see if ecosystems are healthy, detect earthquakes more rapidly, predict traffic patterns and monitor energy use. The idea is that accidents could be prevented and energy could be saved if people knew more about the world in real time, instead of when workers check on these issues only occasionally.
HP will take its first step toward this goal in about two years, said Pete Hartwell, a senior researcher at HP Labs in Palo Alto. The company has made plans with Royal Dutch Shell to install 1 million matchbook-size monitors to aid in oil exploration by measuring rock vibrations and movement, he said. Those sensors, which already have been developed, will cover a 6-square-mile area.
That will be the largest smart dust deployment to date, he said.
You can learn more about HP's efforts to create a "Central Nervous System for the Earth" (also known as CeNSE) in this video:
More info: How Microcontrollers Work