KentuckyFC writes “The way radio signals vary in a wireless network can reveal the movement of people behind closed doors, say researchers who have developed a technique called variance-based radio tomographic imaging which processes wireless signals to peer through walls. They’ve tested the idea with a 34-node wireless network using the IEEE 802.15.4 wireless protocol (the personal area network protocol employed by home automation services such as ZigBee). The researchers say that such a network could be easily distributed by the police or military wanting to determine what’s going on inside a building. But such a network, which uses cheap off-the-shelf components, might also be easily deployed by your neighbor or anybody else wanting to monitor movements in your home.”
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