Receiving a Wi-Fi signal through a couple of thick walls is often a major headache, but researchers are trying to make the best of the signal's weakness. By measuring signal strength, researchers at University of California, Santa Barbara have figured out a way to use Wi-Fi to see through walls. Their method works by having two autonomous robots make their way around an unknown structure, with one sending a signal off to another. Eventually, the receiver will collect enough data about where the signal is strong and weak to build a two-dimensional picture of what it's been looking at.

In a video, the researchers use a hollow square of bricks with a pillar in the middle as an example of how this can work. At first, the robots see the pillar as an entire wall, but as they continue to scan, it becomes clear that there is empty space around around the column. The robots' final image is by no means crystal clear, but it's accurate enough that it would allow an observer to get a fairly good sense of the structure. And while the video shows the robots moving in a very organized fashion around a simple object, the researchers suggest that a more randomized path might allow them to also work effectively in areas that present obstacles to their movement.