Mount the Brinno Digital Peephole viewer on your home door, and it allows you to examine whoever knocks on your door on its 1.3MP display. It also allows me to write bad puns on the headline.
Outside it looks like a normal peephole. Inside, the $US160 device gives you two kinds of view: Regular and zoomed, which can be switched with a single front button. According to the manufacturer, it runs on two batteries for up to 1700 peeps. [Bold Technology via Red Ferret via Unplggd]