Use an Arduino to Build Your Own Secret Knock Escape Room Puzzle

For the average person, an escape room is a great excuse to hang out with friends in a unique setting and work together to solve fun puzzles. For makers, escape rooms offer an opportunity to figure out how the puzzle mechanisms were built, and how you might design your own. The more the puzzles rely on technology, the more interesting they are. In the newest video from the YouTube channel Playful Technology, you can learn how to build a secret knock puzzle with an Arduino.

Using this secret knock puzzle is straightforward, and you may have even seen one in an escape room yourself. Somewhere in the escape room the players find or deduce a secret knock pattern. Then, they have to knock that pattern out on a door. If they get it right, the door unlocks and opens. But, how does it actually work, and how can you build your own?

It’s actually not too difficult if you’re used to working with an Arduino. You can use either a Piezo pickup or a regular microphone. In both cases, the Arduino is programmed to listen for level spikes that correspond to the knocks, and checks the time delay between them. If the pattern matches the programmed secret knock, a magnetic lock is disengaged and the door opens. The same basic setup can be used in a variety of escape room applications, and Playful Technology has a number of other tutorials on how to build escape room tech.