Wooden box repeats rhythm used when knocking on the lid


[Paul Mandel] just finished building this knock box project. It’s a familiar concept that uses a solenoid to tap on the side of the box. The Arduino driven setup monitors vibrations on the lid. When you knock on the box, it records the pattern and plays it back using the solenoid.

He was inspired by a knock-detecting door lock. Using that code as the starting point he implemented a system that takes input from a simple push button and echos back the rhythm using the Pin 13 LED on the Arduino board. This is a great way to start as it removes the complexity of driving a solenoid and monitoring a piezo element. After a bit of success he implemented each of those hardware modules one at a time. You can get a look at the final product in the clip after the break.

One of our favorite version of this project is still the knock block from several years back.


  1. Circuitmage says:


    Interesting idea….novelty item? Halloween prop? Hmm….

  2. bunedoggle says:

    Love the last knock, priceless.

  3. wetomelo says:

    Love The Opto22 Solid State Relay!

  4. qwerty says:

    If it detects correctly the distinctive begin of YYZ by Rush, I’m getting one right now!:)

  5. anomdebus says:

    Along the lines of the last knock, it would be cool to have a challenge/response to unlock a door.

  6. Evil.Spock says:

    It would have been more effective if the solenoid struck the center of the box’s lid instead of the edge. Other than that, nice build.

  7. Sammal says:

    Cool! This is like a reversed version of the Android game “Rhythm Sheep” :)

  8. I think the inspiration for that last bit was taken from a classic slap-stick comedy from the 40s or 50s. Possibly Abbot and Costello.

  9. tk says:

    How about turning it around. Let the box produce knock sequences, and you have to repeat them. Creating a game with longer and longer knock sequences.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Get every new post delivered to your Inbox.

Join 96,700 other followers