The Defense Advanced Research Projects Agency (DARPA) has funded some strange projects in its work to develop new technology for the United States military. But perhaps none quite so strange as using coffee grains to pick up an egg.

DARPA provided some of the money for a newly published study involving researchers at universities in Chicago and New York and the iRobot corporation (who produces the Roomba robotic vacuum cleaner). They’ve produced a robotic arm which, rather than having a claw-like device at the end, has a balloon filled with coffee grounds.

The device works because the surface of coffee grains changes under pressure. As Hod Lipson, one of the researchers explained, ” When they are not pressed together they can roll over each other and flow. When they are pressed together just a little bit, the teeth interlock, and they become solid.” Rice and sand have similar qualities but are heavier.

That’s the reason why vacuum-packed coffee feels much more solid than when the grains are loose. That effect is recreated in the robot by air being sucked out of the balloon. This effectively “solidifies” the balloon, holding its shape and allowing it to hold on to any object it was surrounding.

There are some practical benefits to the device, beyond simply being awesome. It works well even with objects that human aren’t able to handle such as coins (which are fiddly, particularly when laid down) or eggs (which need a relatively precise and controlled degree of grip to avoid messy results.) While the robot might seem an over-engineered solution when you think of the “hassle” for a human to pick up one such object, it could make a major difference in assembly lines such as egg packing or coin sorting.

The researchers also say the technique could be used for handling sensitive objects as part of a bomb disposal team’s work. Though I must admit I’d be tempted to drop the bomb just to smell that freshly roasted coffee goodness (albeit with a rubbery aroma.)

The results of the study have been published in the Proceedings of the National Academy of Science. The researchers say there’s no reason why the device couldn’t be manufactured commercially right away.