Can't be bothered with keys but still need a way to prevent intruders from invading your fortress of solitude? Try a secret knock detector to guard your lair. Don't know how to build one? Stephen Hoefer over at Make demonstrates: However, if you live in a shoebox New York City apartment like some of us, where everyone in the building can hear you knocking, this probably won't be very helpful. Related Content: Discoblog: How To Build A Computer Inside a Deceased Beaver Discoblog: U.S. Army Bases Powered with Energy from Garbage Discoblog: Brain-Computer Interface Lets You Communicate Your Thoughts Throught the Web (Without Blogging)
Video: Stephen Hoefer / Made
