Sesame's smart door lock lets you in with a simple knock
 

There's no shortage of smart door locks, but they typically require that you bring out your phone or enter a code to get in. Wouldn't it be nice if you could just knock, like you're visiting a friend? Candy House thinks that's a decent idea. It just ...

http://www.engadget.com/2015/02/25/s...=rss_truncated