Knocklock - Knock To Unlock An Electric Strikestar rating 3Randy PeckDecember 8, 2011We have used a Knock Lock to open a secret bookcase door for several years now, and it has performed flawlessly. The reason for the 3-star rating is because it uses the same device for input and output. That is, a simple microphone is used both to listen for knocks and also to "chirp" back the signals indicating if your knocks are received and correct or incorrect. This is a problem because the volume of the chirps is too loud and cannot be controlled. If you insulate the "speaker" then you are insulating the "microphone" and it can't hear the knocks. So the result is that a fun and mysterious way to open a door gives itself away as an electronic gadget that beeps like a children's toy. I'd be much more happy with a version that supported a way to disable to chirping or at least turn the volume way down. I would still recommend the product because it works great and I don't know of any other option.
Knocklock - Knock To Unlock An Electric Strikestar rating 5RobertDecember 4, 2009Has worked for over 2 years and still running on the original AA batteries.
Knocklock - Knock To Unlock An Electric Strikestar rating 5amjadJuly 29, 2009great product
Knocklock - Knock To Unlock An Electric Strikestar rating 5Evan KaymenAugust 11, 2009We have used the knocklock a few times now and really love it. It is the perfect interface for an installation when you want nothing showing on the outside of the door. It has always worked flawlessly.