A professor and a team of students from the University of California, Santa Barbara have found another use for WiFi; they can tell how many people are in a designated area, without having a person being connected to the WiFi device. The innovation was previously used by Yasamin Mostofi (Professor of Electrical and Computer Engineering) to look inside rooms; however, instead of distinguishing the location and outline of fixed items within an area, the variations in the WiFi’s signals were used to calculate how many individuals and objects were standing, walking or running in that particular location.
To test out their discovery, scientists placed two WiFi cards at opposite ends of a 750 sq ft area. By making use of the received power measurements of the link between the two cards, they were able to identify how many people were walking in that area. This mainly relied on two key factors – a decrease in the signal as a person crosses between the two WiFi devices and when a human body scatters the signals. These scattered signals are then reflected back to its source card and with the basic calculations, the scientist are able to determine how many people crossed. This method is called multi-path fading. The researchers have successfully tested the technology in both indoor and outdoor environments. It is believed this application of WiFi can be used in energy efficiency, search and rescue missions, and in commercial business.
“Stores can benefit from counting the number of shoppers for better business planning,” says Mostofi. According to Yasamin, if used with a developed system, the technology could assist with energy efficiency efforts. For example, the ability to estimate the number of people in a building could be used in smart homes and building, allowing air conditioning and heating to be adjusted according to the level of occupancy. Something similar to the Nest Technology. Mostofi says she plans to bring the two WiFi-based projects together.