<p>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 <a href="http://grathio.com/2009/11/secret-knock-detecting-door-lock.html" title="">Make</a> 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: <a href="http://blogs.discovermagazine.com/discoblog/2009/10/01/how-to-build-a-computer-inside-a-deceased-beaver/" title="">How To Build A Computer Inside a Deceased Beaver</a> Discoblog: <a href="http://blogs.discovermagazine.com/discoblog/2009/10/06/u-s-army-bases-powered-with-energy-from-garbage/" title="">U.S. Army Bases Powered with Energy from Garbage</a> Discoblog: <a href="http://blogs.discovermagazine.com/discoblog/2009/10/07/brain-computer-interface-lets-you-communicate-your-thoughts-throught-the-web-without-blogging/" title="">Brain-Computer Interface Lets You Communicate Your Thoughts Throught the Web (Without Blogging)</a></p><div class="vert-display-toggle collapsible relative flex flex-col items-center "><div class="vert-unit mt-4 mb-3 top-20"><div ad-type="mobile-desktop" class="ad-wrapper vert min-h-boombox flex items-start justify-center" data-ad-mapping="inline" data-ad-slot="Discover/inline-ad" id="div-inline-ad-0"></div></div><span aria-label="Advertisement" class="text-ad mt-1 text-[11px] uppercase">Advertisement</span></div><p><em>Video: </em><a href="http://grathio.com/2009/11/secret-knock-detecting-door-lock.html" title="">Stephen Hoefer / Made</a></p>

Discover how a secret knock detector can guard your lair and prevent intruders from getting in. Build your own with expert guidance!

Technology

Superhero Tip: Protect Your Secret Lair With a Secret Knock Detector

Article

News

Brett Israel

Science

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

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