MIT Creates Building Blocks for Shape-Changing Smart Devices

MIT engineers built modular blocks that reshape into thousands of configurations while keeping their electrical connections fully working.

Imagine a chair that folds itself into a table, or a robotic gripper that reshapes itself on the fly for a new task. MIT engineers just built the modular parts that could make devices like that actually work.

The team calls their invention “bifur-circuits.” These are 3D-printed building blocks that snap together into an enormous range of shapes, while keeping a working electrical connection no matter how the structure is twisted, compressed, or rearranged.

Why Keeping the Circuit Alive Is the Hard Part

Reshaping a physical object is one problem. Keeping it electrically “smart” while it reshapes is a much harder one.

Most shape-changing structures lose their wiring the moment they bend or fold. Bifur-circuits solve that by routing conductive material directly inside each block. So when two blocks connect, they automatically activate a working circuit between them.

That means the structure can sense its own shape and communicate that information out, without any external wires threading through it.

Building on Metamaterials That Bend and Twist

Bifur-circuits are a type of mechanical metamaterial. These are programmable 3D structures made of repeating units that bend or twist in very specific ways when you push, pull, or squeeze them.

The MIT team specifically built on “auxetic” metamaterials, a category that gets wider when stretched, instead of narrowing like normal materials do. In earlier work, the same researchers used auxetic metamaterials to build reconfigurable antennas that could form three different shapes.

Three shapes was the limit of that older design, though. The new bifur-circuit system needed to do much more.

The Trick: Mechanical Bifurcation

The breakthrough came from a property called mechanical bifurcation — a sudden shift in how a structure behaves once force on it crosses a tipping point. Think of gently bending a plastic ruler: nothing much happens until you cross a threshold, and then it suddenly buckles.

In bifur-circuits, that buckling behavior happens in a controlled way as blocks rotate around a pivot point. It lets connected blocks lock into far more stable configurations than a single block could manage alone.

“Bifurcation allows us to significantly expand on this reconfigurability space,” said Marwa AlAlawi, the study’s lead author and an MIT mechanical engineering graduate student. “Just adding one extra unit gives us so many more combinations out of the same structure.”

Add more blocks, and the number of possible shapes grows exponentially.

Built Tough: 10,000+ Compressions, Zero Degradation

Electronics that bend and twist tend to wear out. So the team pushed their design hard to see if it would hold up.

Researchers compressed the reconfigurable structures more than 10,000 times. The electrical connections showed no degradation at all, even after that much repeated stress.

Getting there wasn’t simple. The team had to find a conductive material flexible enough to bend repeatedly, while still moving electricity efficiently. “The conductive material was a constraint we had to work around in the design process, and it dictated how the sensing between blocks would happen,” AlAlawi said.

From a Chair to a Game Controller

To show what bifur-circuits can actually do, the researchers built working demos, not just prototypes on paper.

One example: a chair that transforms into a tea table with storage, then flattens completely for stowing away. The structure senses which shape it’s currently in and sends that information to an electronic display in real time.

Another demo is a shape-shifting game controller. Depending on how you reconfigure it, the controller launches a different video game.

The team also built a software tool that generates instructions for a multimaterial 3D printer, so an entire reconfigurable object can be fabricated in a single pass rather than assembled by hand.

Where This Could Actually Get Used

The researchers see several real-world directions for this technology. Shape-changing antennas could adjust their frequency by physically reshaping, instead of relying on bulky moving parts. Reconfigurable robotic grippers could switch shapes for different tasks while staying electrically connected throughout.

Other possibilities include assistive furniture that helps people change body positions while recovering from an injury, interactive rehabilitation tools, and reconfigurable shelters that could adapt to changing conditions after a natural disaster.

“Bifur-circuits are one step toward developing mechanical building blocks with integrated intelligence,” AlAlawi said. “It would be interesting to build on this work and come up with building blocks that allow us to create a structure with any form or shape we want, and which are structurally stable and can be actuated.”

What’s Next

The research was led by AlAlawi, along with co-senior authors Ticha Sethapakdi, an MIT electrical engineering and computer science graduate student, and Stefanie Mueller, an MIT associate professor who leads the Human-Computer Interaction Group at CSAIL. Additional collaborators came from the University of Tokyo and the University of Michigan.

The work will be presented at the ACM Symposium on User Interface Software and Technology. Looking ahead, the team wants to add more interactivity to the structures and explore additional metamaterial shapes beyond what bifur-circuits currently offer.