Sensors are edging their way into news quite frequently now. SJ Mercury News has a story on smart dust (a wireless sensor network).
It works this way:
Make sensors that are very cheap and very small. They can measure anything you like, from vibration to light levels; or they can perform more complicated tasks, such as taking pictures or analyzing chemicals.
Attach them to the smallest and least powerful computer that will do the job. Cut the power requirements to a bare minimum by allowing the computers to relay messages to one another, and then onto a central receiver, via radio.
Then scatter them by the dozens, hundreds or thousands to keep watch on just about anything.
Because the network examines a problem from so many vantage points, it can produce a much denser and richer picture of what is going on, researchers say.