Wouldn’t it be cool if you could just knock on your front door, and have it open automatically without having to fumble around with your keys, then you might need one of these Secret Knock Detecting Door Lock’s which was made using an arduino, a motor and a piezo sensor.

Check out the video of it in action below, if someone just knocks on your door, it wont open, but if the use the secret knock which can be programmed into the gadget, the door will automatically unlock.

Very cool I think I may have to get one of these installed in the Geeky Gadgets office, although knowing our luck some would-be thief would probably figure out the secret knock.

via Hack N Mod