Smart Dew will find you
The world is a small place these days. Our computers and cell phones keep getting smaller, more powerful and more functional. If you take just a couple of the many functions that these devices can do you can put them in a tiny package called Motes. Tel Aviv University Professor Prof. Yoram Shapira is trying to market these devices as high tech security systems. So how do motes they work? Due to their small size and extremely low cost (25 cents per sensor) many of these small sensors of various types (sounds, vibration, light, humidity, magnetic, temperature, etc.) could be placed around a large facility to relay information to a central system via an ad hoc network that the sensors facilitate. Since they are so small and can be place almost anywhere they can avoid easy detection and it is unlikely that all the sensors could be located in a reasonable matter of time.
This is not new technology, but rather an interesting new application. DARPA has been investigating the utility of motes for a while. On a modern battlefield an array of motes can be placed by personel or dropped from an airplane. Magnetic and vibration sensors would allow information about troop and armor units to be relayed back to a central computer to be analyzed for action or follow up analysis.