Apparently I missed the original as well! - it's at: http://grathio.com/2009/11/secret-knock-detecting-door-lock.html http://grathio.com/2009/11/secret-knock-d

Apparently I missed the original as well! - it's at: http://grathio.com/2009/11/secret-knock-detecting-door-lock.html http://grathio.com/2009/11/secret-knock-detecting-door-lock....