Wi-Fi signals may one day save a person’s life, claim researchers who have proved that these can be used to count people in a given area. Apart from this, the technology may find its way into smart homes or buildings for the purpose of energy efficiency. Imagine a lighting system which can autonomously control how energy is consumed based on how many individuals are in a room and where they’re seated.
The wireless signals do not need to connect to Wi-Fi enabled devices being carried by the people in a given space, in order to make a headcount. It would be impractical because not everyone owns such gadgets. Professor Yasamin Mostofi at the University of California, Santa Barbara and her team have built a system which uses the measurements of a Wi-Fi link to count the number of folks within a certain area.
Mostofi’s experiment involved placing a couple of Wi-Fi cards across from each other within a 70-square meter region. Then volunteers were asked to walk around within these boundaries. The technique leans heavily on the changes in the received wireless signal. When someone walks across the direct line of sight between the two Wi-Fi cards, the signal gets scattered. This is called multi-path fading.
Based on a probabilistic mathematical framework fed into the program, it is possible to make a guess of how many persons are within the given space. Mostofi and her team have successfully replicated the results using up to 9 individuals for indoor as well as outdoor environments. The study will be published in the Institute of Electrical and Electronics Engineers Journal on Selected Areas in Communications.
Mostofi previously worked on employing Wi-Fi signals for imaging stationary objects and humans through walls. She plans to combine the new findings with the older one in the future.