I Turned My Home Into a Fortress of Surveillance

In America, a home is a castle, for better and worse. Thanks to John Locke’s labor theory of property, the American Dream, mortgage-interest deductions, suburbanization, and all the rest, this castle doctrine became a life philosophy for the middle class: Your house is an extension of yourself. Protecting your property—and the people and things that reside inside—is your duty, and your right.

Home-security systems of all kinds, from guard dogs to alarms, have scratched this itch for decades. More recently, smart sensors, cameras, and other devices have taken up the task. With an internet-connected camera, you can check on the home front from work or school or Target.

There are downsides. Internet-connected smart cameras, microphones, , and other sensors send reams of data back to the big, the device’s owner might not anticipate. Smart cameras can magnify and spur .