On Star Trek: The Next Generation the crew had access to a Replicator that would create (food) objects upon verbal command. Although the technology for a real life replicator is still in the future, scientists at MIT have developed a robotic system of spontaneous recreation using "smart sand". The shape duplication process could be used to recreate a broken tool.
Credit: M. Scott Brauer
Scientists at the Distributed Robotics Laboratory (DRL) at MIT's Computer Science and Artificial Intelligence Laboratory have tested geometric algorithms on 30 square millimeter cubes that contain limited microprocessors and electropermanent magnets on four of the six sides. The cubes use a subtractive rather than additive method. A subtractive method works like ice carving. An artist starts with a block of ice. The unwanted material is chipped away until what remains is the desired shape. By communicating with each other, the smart cubes can determine which ones are unwanted material and fall away just as the leftover ice falls to the ground.
Photo: M. Scott Brauer
This video gives a better visual understanding of how the process works.
The algorithm can be used two ways: to produced multiple same-sized copies of an original, or to produced one scaled-up copy. There are innumerable practical applications for this technology. An auto-parts store, for example, need only carry one version of each tool or part instead of multiple packages of the same item. When a customer comes in to by a part, the clerk could throw the original in a box of smart sand, hit a button to start the copy process and pull out an exact replica to sell to the customer.
To perform this process would require grains of sand much smaller than the 30 square millimeter cubes developed at MIT. Robert Wood, associate professor of electrical engineering at Harvard University says, "The core functionality of [MIT's] pebbles... 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. It would take quite a lot of engineering to do that, of course. That’s a well-posed but very difficult set of engineering challenges that they could continue to address in the future."
Now if it only could make a good cup of hot Earl Grey tea.
Read More: "Self-sculpting sand" article at MIT News