"We felt like it would be possible to develop laboratory quantities of sub-millimeter catoms within five years or so given a few million dollars of research investment," said Campbell. "But working at such small scales is much more expensive, and we weren't able to pull together that level of investment at the time." Goldstein's lab continues to work on the project.

Smart Dust

Instead of packing those microscopic nodes with components that make them clay-like, we can pack them with sensors. In 1997, Kris Pister from the University of California, Berkeley explored this possibility on behalf of DARPA in a research proposal titled "Smart Dust".

Each 'mote' of smart dust floats in the air, containing a power supply, a sensor, some circuitry and a way to communicate with other nodes. They could measure anything, from temperature, moisture and movement to chemical signatures and brainwaves. Because they're so small and innocuous, they can be everywhere. If you thought the NSA's data collection was scary, you'll definitely want to keep an eye on this.

The concept has diversified somewhat since Pister's original proposal, and now the leading research in the field is done at the University of Glasgow in John Barker's nanoelectronics laboratory. He explains how they could be used in military applications, but also for space exploration.

"Swarms of smart dust might be packed into nose cones of planetary probes," he says, "and subsequently ejected into the atmosphere of a planet where they would be carried by the wind."

Utility Fog

But perhaps the most fascinating possibility of all comes from combining aspects of both claytronics and smart dust. Utility fog is a phrase coined by John Storrs Hall in 1993 that describes a collection of microscale robots called "foglets" that spread out widely under normal situations but lock together as a solid when commanded in any shape.

Hall envisioned one possible application as a nanotechnological replacement for seatbelts - you could move around in your car as much as you liked, but if an accident was detected the foglets would momentarily freeze the air around you into a safety net, locking you in position and spreading the impact across millions of tiny links.

He explained that it could even take the place of buildings, vehicles or more. "It can look like a park, or a forest, or if the population is sufficiently whimsical, ancient Rome one day and Emerald City the next," he said. "It can act as shelter, clothing, telephone, computer and automobile. It will be almost any common household object, appearing from nowhere when needed (and disappearing afterwards)."

Hype Cycle

These technologies may sound far-fetched but will dramatically change the world around us - and it's only a matter of time until they do.

Smart dust has already made an appearance on Gartner's hype cycle for emerging technologies, right at the ground level with more than 10 years until it reaches the 'plateau of productivity'.

The manufacturing processes that'll deliver these kinds of products are still in their infancy, but with a more development - and what Gartner describes as "a better understanding of human context, humans and human emotion" - the world beyond the Internet of Things could be a very different place indeed.