Image 1 - Algorithm Paves Way For Future 'Smart Sand'
April 3, 2012

Algorithm Paves Way For Future ‘Smart Sand’

Lee Rannals for

Researchers from MIT have developed new algorithms that could enable "Smart Sand" to form into any shape.

By using the algorithm, individual Smart Sand grains would be able to communicate to one another, forming a three-dimensional object.

As messages are passed back and forth to each of the grains, they selectively attach to each other to form an object, while the unused grains simply fall away.

Once the object has served its purposed, the smart sand grains would then detach from each other, falling back to its original state, ready to form another shape.

The researchers had to develop an algorithm that would offer every grain of sand the ability to store a digital map of the object to be assembled.

During a video demonstration of the algorithm in a two-dimensional format, the grains work by first passing a message to each other to determine which have missing neighbors, creating empty areas in the structure.

This empty area displays a shape, in which the grains can take notice of to pass the message along to other grains to form.

Once the shape is formed, the empty area is filled in, and the object being formed by the Smart Sand is left.

The researchers used cubes, or "smart pebbles", to test their algorithm on a simplified two-dimensional system.

Four faces of each cube have electropermanent magnets, which are materials used to magnetize or demagnetize a single electric pulse.

The magnets on these cubes can be turned on and off, and do not require a constant current to maintain their magnetism.

The pebbles use the magnets not only to connect to each other, but also to communicate and share power.

Each pebble has a microprocessor that is able to store 32 kilobytes of program code, and only has two kilobytes of working memory.

Kyle Gilpin, who worked on the project at MIT along with his professor Daniela Rus, told RedOrbit in an email that "while the Robot Pebbles aren't going to turn into Smart Sand overnight," it will eventually happen.

"It may be 10 years before we see modules capable of forming shapes whose resolution surpasses that of alternative fabrication methods, but we'll see incremental improvements along the way," Gilpin added.

"Consider how rapidly and dramatically computers have been miniaturized over the last 50 years.  What used to occupy an entire room now fits on a small fraction of a fingernail.  We'll see the same advances applied to programmable matter systems as well. "

He said the original inspiration for the concept of Smart Sand derived from the way a sculptor shapes their stone.

"Just like a sculptor removes material from a block of stone, we remove the extra Pebble modules from the system to reveal the shape underneath," he told RedOrbit. "In many ways, it´s much easier to remove material than it is to add it."

The researchers will be presenting a paper describing the algorithms of their findings at the IEEE International Conference on Robotics and Automation in May.


Image 2: To test their algorithm, the researchers designed and built a system of 'smart pebbles' – cubes about 10 millimeters to an edge, with processors and magnets built in. Photo: M. Scott Brauer