Knock Knock! Who's there? Skybell Version 2.0!

The peephole is a brilliant low-tech invention that lets you see who's at your front door without having to open it. But it requires you to put your eye right up to the hole, putting you in very close proximity to the person on the other side.

The folks at Skybell had a better idea: A device that replaces your doorbell with a Wi-Fi camera and intercom, so that you use your smartphone to see--and talk to--the person on the other side of the door. Their 2013 crowd-funding campaign was a huge success, and today they're shipping Skybell version 2.0.

"We launched on Indiegogo on August 15 [2013], with a target of $100,000," Skybell co-founder Andrew Thomas told me in a recent interview. "We raised $100,000 in the first five days. Between that and Amazon pre-orders, we recorded $2 million in product sales before the device went into manufacturing."

Skybell contains a wireless video camera, a two-way radio, and a wireless-networking module that connects to your home Wi-Fi. When someone pushes the button to ring your doorbell, Skybell's cloud-based server sends a push notification to your smartphone to initiate a session with one-way video (so you can see them, but they can't see you) and two-way audio (if you want to speak with the person). You don't need to go to the door to see who's there; heck, you don't even need to be home. And you can configure the device to send alerts to multiple mobile devices if you want more than one person to receive them.

Skybell depends on the low-voltage wiring that powers your existing analog or digital door chime and transformer; so you might need to do a little wiring if your home uses a battery-powered doorbell, as mine does. The device does have a backup battery, should your home suffer a blackout. A silent mode will turn your door chime off if you don't want to disturb someone at home, or if you have the type of pet that freaks out every time the doorbell rings. The Skybell doesn't require a visitor to push the doorbell button to initiate a session, they just need to get close enough to trigger its motion sensor.

Thomas and his crew took everything they learned building the first version of Skybell and made a host of improvements for the second version. The night-vision-capable camera has a 140-degree field of view, sufficient to capture an image within a five- to six-foot radius of the center of the camera. And version 2.0 comes with a faster Wi-Fi module and more memory that enables faster performance--you can see out of the camera in less than five seconds--and the ability to support additional features down the road, including a server recording feature and a daily activity list.

To install a Skybell, you'll need a 2.4GHz, 802.11b/g/n Wi-Fi router and a broadband connection capable of upload speeds of at least 1.5Mbps and download speeds of at least 1.0Mbps. The Skybell app is compatible with Android 2.X or later and iOS 6.1 or later. The original Skybell was available only with a brushed-aluminum finish; the new version is also available in an oil-rubbed bronze finish. Skybell 2.0, which is designed and manufactured in California, costs $199 and is available at Amazon, Best Buy, and direct from Skybell.

Would you consider adding a camera-enabled doorbell to your front door, or do you think $200 would be better spent on a snarling dog that would deter anyone from approaching your front porch? Share your thoughts with us in the comments section, below.