How a new Wi-Fi 'localizer' could create smarter homes, safer drones

Losing a signal or getting kicked off a Wi-Fi network can often be an inconvenience or a disruption. It can even lead to theft -- though of a relatively harmless variety -- with 32 percent of users telling an industry trade group in 2011 that they had stolen a neighbor's Wi-Fi in order to go online. But instead of a desperate search, what if a Wi-Fi signal could find you instead, even in a room full of people all using the same network? That's the idea behind a new system developed by researchers at MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL). It finds a particular user by calculating the "time-of-flight," a measurement of how long it takes for a signal to travel from a user's computer or phone to a single Wi-Fi source.