Until now the role of wireless in motion detection has been confined to communicating the information, but now it is ready to become the sensing medium as well. There are a few emerging consumer systems available, but the most significant development so far has come from Quantenna, which has incorporated wireless motion sensing in its WiFi chips. This has a similar range of applications to conventional visual detection systems such as security cameras, but with some clear advantages. Among these are avoiding need for new hardware, because motion detection can be added as a software upgrade to wireless routers and repeaters already present in many homes and businesses. It also does not rely on line of sight so provides ubiquitous…