You have probably heard someone say something like "we're living in 2022! Where are our flying cars and robots?" But the truth is that we're surrounded by robots — they're downright commonplace. However, most are single-purpose robots, like your Roomba that exists only to vacuum your floors. What people imagine when they think of "the future" is a world full of general purpose robots that can do many tasks; a Rosie compared to that Roomba. To bring us closer to that future, MIT CSAIL engineers created magnetic robots that assemble like Voltron.
The concept of small, modular robots that can self-assemble into many larger robot configurations isn't a new. But the challenge is always actuation — how can the robots reconfigure themselves? Many previous solutions were expensive and complex. But this system, dubbed ElectroVoxel, solves the problem using electromagnets. Those electromagnets are simple, easy to build, affordable, and don't require any moving parts.
Each ElectroVoxel cube robot has electromagnets lining each the edges on its 3D-printed frame. By controlling the polarity of those electromagnets, they can force adjacent robots to stick to eachother. They can also use attractive and repulsive forces to pivot one robot relative to another. So a robot sitting on top of another can pivot 270 degrees in order to swing around and sit next to the second robot. Put many of these together and you've got a robotic system capable of rearranging itself into many shapes.
ElectroVoxel robots do not require tethers and utilize an Arduino Nano board with an integrated nRF24L01 module for control. But there is a major catch: they currently only work in microgravity. In normal Earth gravity, the electromagnets aren't strong enough for the pivot actions. To test the robots, the MIT CSAIL team had to experiment on a parabolic flight that simulates microgravity.