WATCH THIS: The computer that runs on water droplets

Alan Martin June 11, 2015

Computers and water aren’t natural bedfellows, as anyone who has spent a day drying out their smartphone in a box of rice will tell you. But researchers at Stanford University have broken with tradition by designing a computer that runs on water droplets.

The chips are around half the size of a postage stamp, with droplets of water are a touch smaller than poppy seeds – but the researchers believe there’s scope for things to get smaller with time.

Here’s how it works. A series of tiny iron bars are held in a layer of oil between glass slides to make a computer clock. Water droplets infused with magnetic nanoparticles are injected into the system, and are then manipulated by a magnetic field flipping the polarity of the bars. As the Stanford press release explains, “Every time the field flips, the polarity of the bars reverses, drawing the magnetised droplets in a new, predetermined direction, like slot cars on a track. Every rotation of the field counts as one clock cycle, like a second hand making a full circle on a clock face, and every drop matches exactly one step forward with each cycle.”

Confused? Check out the video below to see it in action.

Although these water-drop chips work in broadly the same way as our current computer chips, the whole process is markedly slower. That’s isn’t too much of an issue however: they’re not trying to compete with electronic computers.

“Our goal is to build a completely new class of computers that can precisely control and manipulate physical matter,” explained Manu Prakash, assistant professor of bioengineering at Stanford. “Imagine when you run a set of computations that not only information is processed, but physical matter is algorithmically manipulated as well. We have just made this possible at the mesoscale.”

In other words, because the computer runs on liquids rather than electronics, the materials involved needn’t just be magnetised water. Each droplet could carry a different chemical, becoming its own miniature test tube. The droplet computer offers a level of control never seen before, giving it huge potential in the worlds of chemistry and biology.

Could this, as Gizmodo speculates, lead to a world where these computers are small enough to swallow, and combine custom medications on the fly with droplet chemicals? We hope so.

Prakash certainly has high hopes for the project, inviting groups or individuals to work on their own blue-sky solutions. “We’re very interested in engaging anybody and everybody who wants to play, to enable everyone to design new circuits based on building blocks we describe in this paper or [to] discover new blocks. Right now, anyone can put these circuits together to form a complex droplet processor with no external control – something that was a very difficult challenge previously,” he said.

“If you look back at big advances in society, computation takes a special place. We are trying to bring the same kind of exponential scale up… into the physical world.”

Although they might initially seem like a technological backwards step, water-powered computers could help solve some elusive problems – with a little outside-the-box thinking and a dash of H2O.