"All the components we use are ones typically used in a Wi-Fi handheld device," she said.
Because of its underlying technology, Wi-Vi also wouldn't represent a big drain on batteries, Katabi said.
Bringing wall-penetrating vision to handheld devices could open up a lot more uses for it. Current radar-based systems used in the U.S. military are so big they need to be transported on trucks, Katabi said. Even the Army might need a more portable tool for seeing through walls in certain settings, she said.
Wi-Vi's capabilities might also help searchers find people trapped in collapsed buildings after earthquakes. Police could use it to detect the number of people in a room and their movements, preventing an ambush when they raided the room. Used with a gaming console, it could allow players to walk away from the console into another room and keep playing the game, Katabi said.
Because of its low resolution, Wi-Vi could actually enhance people's privacy rather than erode it in some cases, Katabi said. For example, it could be used to remotely monitor whether an elderly parent had gotten out of bed or gone into the kitchen, without installing video cameras that the parent might find intrusive.
But whether in the hands of police or of ordinary people, a widely available tool to see through walls raises questions that the law hasn't answered, said Hanni Fakhoury, a staff attorney at the Electronic Frontier Foundation.
"Your location is something that's worthy of privacy," Fakhoury said. "We know that, even within your house, where you go can reveal a lot about yourself."
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