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There is always someone watching you, so shouldn't you be watching too?

Once the domain of companies like Panasonic, newer names like Dropcam have made security webcams easier to install and – as a result they are becoming increasingly commonplace. A new crop of models promises more features, with sirens, moisture sensors, and even air quality alerts. I've been testing several models for months and found three of the best cameras for checking on the kids, pets, or to simply making sure things are secure at home when you're away.

Withings Home, $200

Withings has a line of smart devices, ranging from watches and fitness devices to blood pressure monitors and connected bathroom scales. The company's Home security camera is another Internet of Things device designed to boost your home’s IQ.

With its white tubular design, faux wood veneer, and magnetic stand, it looks more like an appliance than a camera, yet it has most of the features available in more nerdy-looking competitors. It includes 1080p video, night vision, two-way audio and Wi-Fi. It can be set to alert you if there's motion, noise, or a change in air quality and it works with iOS and Android devices.

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The Withings Home picture is reasonably clear if a little grainy at times. The camera's software does a nice job of correcting the fish-eye effect so that its 135-degree view looks relatively normal and can cover most of a large room. The app uses a daily diary metaphor and contains a handy series of time-lapse clips that give you a quick view of any detected motion.

The Withings Home's air quality sensors will not alert you to the most dangerous airborne threat, carbon monoxide -- none of the models here can do that. What it does do, according to the company, is measure in parts per million volatile organic compounds (VOCs), the noxious vapors that can be released, or “off-gas” from plastics and paint, causing headaches, and, potentially, cancer. I never recorded any air issues, but I did find the feature reassuring.

The Home camera will keep 2 days of alerts and time-lapse recordings for free. If you want more, there's a monthly $7.95 subscription that gives you a week of recordings; for a month of coverage, it's $19.95.

Canary, $199

Like the proverbial bird in the coal mine, the Canary camera is intended to be an early warning system.

The Canary has an HD 1080p camera with good night vision, plus a reliable motion sensor to trigger recordings and ambient sensors for temperature, humidity, and air quality. There are even accelerometers should an earthquake ensue. Tying it all together, the Canary uses built-in Wi-Fi and a slick app that runs on Android and iOS devices.

The main attraction of Canary is its excellent picture quality compared to other webcams. Color fidelity and image detail is more than sufficient to identify a person entering a room, and video playback is smooth with good sound. You can watch a live stream from your phone and sound a siren to scare intruders away (or make Fido jump off the couch). The system can also be set to automatically arm itself whenever you leave the house, and it can be adjusted to recognize other family members so that it only switches on when everyone is away.

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Canary is not without its flaws, however. It requires a special supplied cable to perform the installation (you connect it to your smartphone during setup), which can be a problem if you have to move the camera later and misplace the cable. The Canary is also a bandwidth hog. In order to see its live stream you need a 1-megabit-per-second connection. That means typical DSL lines supporting other devices at home usually aren't sufficient; you'll need a cable or fiber optic connection. Furthermore, to fully enjoy Canary's security features, monthly fees like those for the Withings Home are required: You get access to events from the last 12 hours for free, but it costs $4.99 a month for a two-day timeline ramping up to $29.99 for 30 days of recording online.

Piper NV, $279

The NV in Piper NV stands for night vision, a feature lacking in the first Piper model. The latest model is more flexible, with excellent networking abilities and a wide 180-degree view that can spy on an entire room.

The Piper NV delivers crisp 1080p video and offers many of the same features and alerts as the models above. It monitors indoor and outdoor temperature and humidity and can let you know about local weather alerts. Piper conveys temperature, noise, motion, and humidity trends in colorful graphs. So I could see, for example, that no one had been in my garage while the temperature had been trending steadily up in the last two days. Its fish-eye view covered the entire area and it was one of the few cameras I've tested over the years that could connect to my Wi-Fi network from what has proven to be a troublesome location.

Rounding out its features, the Piper NV includes AA back-up batteries in case someone decides to cut the cord. You can also adjust its video data rate, which means that in a home with a flaky Internet connection you can throttle it back so that it doesn't take up too much bandwidth on your network. In addition, the Piper NV acts as its own Z-Wave hub so that it can control additional wireless smart home devices. Piper sells several such accessories, including a door sensor and water sensor for $40 each. It's not an extensive array of offerings, but it's a start.

Piper will store up to 1,000 video clips online for you, and then automatically begin overwriting older recordings. Best of all, the service is free.