Bret Cahill's thread about transducers motivated me to write this article.
Science attempts to determine the quantity of orthogonal properties at points.
For example, one might want to know the three dimensional stresses and strains on a jet engine, and the angular velocity and temperature of the engine.
Historically science and engineering have tried to focus transducers on one property by compensating or "zeroing out" the affects of properties other than the one the observer is trying to correlate with something. ( Failure, noise, vibration, etc.)
I suggest that the best way to find out what is going on at a point, is to attach a transmitter at the point, that transmits a quasi-random code that identifies the point, like the codes used to identify cell phones GPS satellites, migrating birds, etc.
and to modulate the data portion of the signal with orthogonal signals output from a "multiducer", a device sensitive to various properties in the environment,
and develop sophisticated software to separate out the various property components in the signal, much like medical imaging software.
The "multiducer" could be something like a quartz crystal or even a living thing like a bug, or even a more complex animal that has been conditioned to respond to certain environmental conditions.
For example, during WWII, the Germans trained pigeons to peck at a"joystick" to center aerial pictures of places in London, with the intension of using the pigeons as control mechanisms for rocket bombs.
An animal is not only hardwired as a "multiducer" for many properties, (Such as temperature, noise, oxygen level, vibration, etc.) it can be conditioned to identify other properties such as X, Y and Z (Size of the picture), orientation, etc.
For example, you could load a pig, dog, etc. with a WMD, and have it find a Wal-Mart, and to activate it's "payload".
Observe that a "navigatible" "multiducer" could not only transmit information based on it's hard wiring and conditioning (Programming) it could be steered to minimize or maximize various environmental conditions. ( It could approach or avoid noise, temperature, Wal-Mart, etc.)
Come to think of it, the Mass Media and search engines like Google are already "programming" dumb animals to serve as carriers and activators of WMDs,
and things like WWI, WWII, the Spanish Civil War, the Iraqi War, America's Urban Rebellion the various revolutions such as the ongoing ones, General Relativity, etc.