These new surveillance options come at a time of heightened angst about parental supervision. In her memoir “Small Animals: Parenthood in the Age of Fear,” released in August, Kim Brooks chronicles being charged with contributing to the delinquency of a minor after she briefly left her small child alone in a car. She argues that her odyssey through the criminal justice system was a product of a culture convinced that our children are in a constant state of peril and only a vigilant parent can protect them.

“We are living in an age of fear,” she writes. Most of the dangers our children face — a changing climate, a vanishing middle class, spiraling health care costs — are beyond our control. And so our grip on the things we think we can control — like what our children do with their afternoons — grows tighter.

Gone are the days of riding your bike around the neighborhood on your own until dusk. A 2014 Reason-Rupe poll found that 68 percent of Americans thought that a 9-year-old should not be allowed to play in a park unsupervised, and just over half of Americans thought a 12-year-old deserved such independence. Yet more than 40 percent of children are left home alone at times, according to the American Academy of Child and Adolescent Psychology.

Since we’re expected to always be watching even when we can’t, we look to technology to solve the impossible. If we download the right app, maybe we can keep harm at bay, and no one can call us a neglectful mother. Just as parents use GPS tracking devices on cellphones to monitor their children out in the world, parents can point to that camera on the bookshelf as proof that our attention is squarely focused on home, even when it isn’t. With enough devices, we can constantly guard the roost.

But do I really want to know about everything that’s happening in my house? A live feed into my living room means my home is only as safe as the last time I checked. Sure, my son was fine when he arrived, but is he now? How about now? And should he decide to go play with a neighbor, I’ll get a fresh alert reminding me that until that next one chimes, I should be on, well, alert.

“The more you engage in this sort of fear-driven buying and reacting, the more scared and worried and distrustful you’re likely to become,” said Barry Glassner, the author of “The Culture of Fear: Why Americans Are Afraid of the Wrong Things.”

Yet, our children are alone sometimes, and technology can help us know when they’ve gotten home safely. A microphone-enabled camera could make it easier to help children with homework or to intervene in a sibling dispute.