Yo-Yo Machines Kit 3 - Knock Knock

Knock on one Knock Knock box and the other box knocks too (try saying that three times fast). It’s like they’re a single object that somehow appears in two places at the same time. Magic!

Knock Knocks come in pairs and are connected on the internet. The noise made by tapping on the box is is picked up by a piezo sensor inside and used to trigger a solenoid in its remote partner. It’s still kind of magic, if you think about it.

This kit contains everything you'll need to make your automated door knocker!

• 2 x microUSB cable
• 2 x ESP32S board
• 2 x Mini breadboard
• 2 x IRF520 MOSFET module
• 2 x mini solenoid
• 2 x 1M resistor
• 4 x WAGO 2 way connector
• 2 x Piezo Transducer
• Male to male jumper lead selection

The USB cables that are included in the kit will let you power your units from any USB port. If you'd rather plug your device/s into a plug socket you can use a microUSB power supply to do that (not included, but we sell ones that will work here).

Click here for the full build instructions

Knock Knocks are made to be played with when you are both around — once sounds have played, no trace is left behind. But they’re quick, and they’re simple: all you’ve got to do is tap on your box and listen for a reply. What might you do with them?

• Send a quick knock-knock to say hello and indicate your presence.
• A simple call-and-response (‘shave and a haircut’) can give a brief sense of togetherness with your remote partner.
• Try more elaborate rhythm games – the response should be quick enough that you can jam together for hours.
• If you’re bored with social media, maybe its time to learn Morse code?

We build the Knock Knock mechanism into a simple cardboard box, but you can try using the solenoid with different objects and surfaces. You might position it to start a wine glass ringing, in an homage to Droog Design’s droog doorbell doorbell. You could try using it with that cymbal you keep as a reminder of your days in the band. Or maybe attach pins to them and create a situation of mutually assured balloon destruction? Go ahead and play – that’s what they’re for!

We’re from the Interaction Research Studio, a team of designers and technologists at Goldsmiths, University of London. UKRI is supporting us to develop Yo–Yo Machines to show how research can have real-world impacts.

Visit our Yo-Yo Machines Website for more information about the project.

Contact us via email [email protected] or share your designs in the Answers Forum.