Ever wanted to open a lock with a secret knock, [steve] shows us a video of one actully working. The idea is pretty simple, knock in a certain pattern and the door unlocks. We have seen many variations but this one is more easy in practice. The design is not bad, and it is easyly programable. To change the combination of the knock you just hold the red button, Simple!

We’re a bit surprised that the suction cups actually hold it on the door. Maybe it’s just us, but we can never seem to get those things to hold very well. There are lots of great pictures as well as the source code available on his site.

[via HacknMod]