In action movies, the hero never has a problem smashing through doors - one solid kick is all it takes. In reality, gaining access to a locked room is much harder; but not always impossible. This infographic "breaks down" how it's done.
Smart doorbells can snap a photo of whoever rings the bell, making it so you can screen all those visitors you get throughout the day. Over on Instructables, Naran shows you how to build one with a Raspberry Pi.