Nearly everywhere we go today, we're bombarded with Wi-Fi signals. We normally think of Wi-Fi simply as a way to transmit information and keep us connected to the internet – but what if we could use all of these Wi-Fi signals as sensors?
Because Wi-Fi signals lose energy as they pass through different types of objects, Yasamin Mostofi, a professor of Electrical & Computer Engineering at University of California Santa Barbara, wondered if the signature left on Wi-Fi signals could be used to reconstruct what the signal had passed through.
"Our first interest was x-ray vision with Wi-Fi. We basically wanted to see if we can see behind walls with Wi-Fi signals," said Mostofi. "We've shown that you can actually do this."
The resolution of the scan is low, but hide a barrel behind a wall and a scan using Mostofi's Wi-Fi-enabled robots can find the general shape and position without using any visual cues.
Mostofi sees immediate uses for search and rescue. Being able to spot people trapped in collapsed buildings from the outside could quickly direct resources to the areas of need and avoid wasting precious time.
Wi-Fi networks could also enable new smart building technologies.
"Wouldn't it be great if the existing Wi-Fi network can tell something about the density of the people, which areas are more crowded?" said Mostofi.
This type of information could be used to optimize heating and cooling for buildings, and save power on lighting.
Read more: How Wi-Fi Can Give Us X-ray Vision
Watch: Can We Use Wi-Fi to See Through Walls?
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