Back in 2010, researchers from Cornell University helped develop a robotic gripper that was stuffed with coffee grounds. Now, a Cornell team has done the next logical thing, and built soft-bodied robotic devices that are filled with and activated by popcorn.

Led by doctoral student Steven Ceron and Prof. Kirstin H. Petersen, the scientists were investigating methods of powering "inexpensive robotic devices that grip, expand or change rigidity." Popcorn turned out to be a good choice, as it's cheap and readily-available, the kernels rapidly and forcibly expand by more than 10 times when they pop, plus a batch of popped corn is considerably more viscous (and thus stiffer) than a collection of unpopped kernels.

Amish Country Extra Small was the specific brand of popcorn used, due to the facts that it contains no additives that might affect the results, and the kernels had the highest expansion ratio of the varieties tested. It was used in three separate devices.

One of these was a gripper, composed of three silicone fingers stuffed with kernels. As heat was applied to those kernels via an attached nichrome wire, they popped and exerted pressure against the fingers' outer walls, causing the fingers to curl inwards around a target object. A wire was also used to pop 36 kernels lined up inside a floppy silicone "beam," causing it to stiffen into a rigid structure. The third device was an origami-like bellows made from instant popcorn bags – when the kernels inside were popped using a microwave, it expanded enough to lift a 9-lb (4-kg) weight placed on top of it.

It's also been suggested that the technology could be used to propel miniature jumping robots. Needless to say, any such popcorn-powered devices would likely only be good for a single use. Nonetheless, due to their low cost and simplicity (no hydraulics, pumps or motors would be required), they could potentially have valuable applications.

"The goal of our lab is to try to make very minimalistic robots which, when deployed in high numbers, can still accomplish great things," says Petersen. "Simple robots are cheap and less prone to failures and wear, so we can have many operating autonomously over a long time. So we are always looking for new and innovative ideas that will permit us to have more functionalities for less, and popcorn is one of those."

A paper on the research was presented this May, at the IEEE International Conference on Robotics and Automation

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