I remember seeing a similar commercial product. Everything was mounted within a door so it could not be tampered with. the “knock code” was so long and precise it used a small battery powered key to do the knocking.

This would be awesome fun to hack, if some how indicates a mistake you could keep trying, well it would be very hard but none the less fun.

I’m waiting for someone to make one that uses a webcam to detect shadow puppets through the peep hole as a access control method :P

I’m working on (Read: About to start, anytime now :P) a similar setup, but it takes a picture with a webcam through the peephole of whoever knocked. An answering machine, but for your door.

Well, it looks unsafe, but it’s like the apartment entrydoor opener connected to your doorbell, if you won’t know it’s there, no one will brute-force knock you!
and because it’s a empty building, your neighbors won’t get tired from your knock-sequence, so they won’t give it a try someday..
nice hack!

I’d like to try this with a capacitance switch on a doorknob. Or weirder yet, a musical lock with a door embedded theramin.

Would be nice to have one where you’d have to sing a song every time you want to get the door open.
(imagine a scene where you’d have to go to the toilet)

http://www.hackaday.com/category/cellphones-hacks/

I am starting my own blog too, your is really nice!