Wi-Fi can help house distinguish between members

In smart homes of the future, computers may identify inhabitants and cater to their needs using a tool already at hand: Wi-Fi. Human bodies partially block the radio waves that carry the wireless signal between router and computer. Differences in shape, size and even gait among household members yield different patterns in the received Wi-Fi signals. A computer can analyze the signals to distinguish dad from mom, according to a report posted online August 11 at arXiv.org.

Scientists built an algorithm that was nearly 95 percent accurate when attempting to discern two adults walking between a wireless router and a computer. For six people, accuracy fell to about 89 percent. Scientists tested the setup on men and women of various sizes, but it should work with children as well, says study coauthor Bin Guo of Northwestern Polytechnical University in Xi’an, China.

In a home rigged with Wi-Fi and a receiver, the system could eventually identify family members and tailor heating and lighting to their preferences — maybe even cue up a favorite playlist.