Hear that? That's the sound of people around the world scooping burnt cheese out of their toaster after attempting this.
Steve Hoefer at Grathio labs shows off his Arduino based door opener, which responds to knocks on the door bye timing the gaps between the sounds. If the gap matches the programmed knock, it unlocks. Let's never use keys again!
Know a little bit about Arduino and care to make your own? Check out his Instructables post!
From the submitter:
A while back I decided to see how my coffee maker worked. I busted it open and by the time I figured things out, I couldn't put it back together (broken). So I decided I didn't want to buy a new coffee maker and I built this stand for the machine innards. The reservoir was built into the old machine, so I had to add the bottle to hold the water as it heats up. It works great!