This is so cool! The brainchild of Steve Hoefer, the “Secret Knock Detecting Door Lock” attaches to a doorknob and its corresponding lock with suction cups. Upon detecting the correct knock pattern (by default, the classic shave and a haircut), it unlocks the door to grant access.
Have you an opinion, used or been to this object or place? Tell us what you like don't like about it, or post any specs/info about it:
