10mm smart pebbles with microprocessors and magnets. Photo by M. Scott Brauer.
The interface between analog and digital realms is a territory that continues to expand in potential. Once constrained primarily to two-dimensional display surfaces, the threshold between bits and atoms is becoming increasingly three-dimensional, with surreal implications. The following excerpt from MIT's Distributed Robotics Lab (DRL) illustrates the point:
"Imagine that you have a big box of sand in which you bury a tiny model of a footstool. A few seconds later, you reach into the box and pull out a full-size footstool: The sand has assembled itself into a large-scale replica of the model."
This description conveys the aspirations of a technology MIT researchers call Smart Sand, a collection of microscaled blocks that self-assemble to form complex objects based on simple instructions. The idea of a real-time physical object-generator in a sandbox is compelling indeed, and a novel rendition of additive manufacturing (the scientists claim that Smart Sand actually employs subtractive manufacturing, although the individual grains would first be fabricated as discrete objects). The glue holding the "pebbles" together is provided in the form of electropermanent magnets that may be turned on and off with a small electrical charge.
The scientists have been testing their idea using 10mm cubes, with the plan to make much smaller pebbles. "Take the core functionalities of their pebbles," says Robert Wood, an electrical engineer at Harvard University. “They have the ability to latch onto their neighbors; they have the ability to talk to their neighbors; they have the ability to do some computation. Those are all things that are certainly feasible to think about doing in smaller packages.”
The project is currently limited by a number of factors, such as the structural dependability of the magnetic bonds and the physical precision of the sand-pile that forms the three-dimensional birthing matrix. It will also require a few engineering advances to miniaturize the required components into a tinier pebble. Nevertheless, the project has great potential. As Wood summarizes, “That’s a well-posed but very difficult set of engineering challenges that they could continue to address in the future.”