Knock-Knock 🐧

I made a Knock knock device that we use to tell our son that dinner is ready.

Our eldest son's room is on the third floor of our house. Our kitchen and dining room are on the ground floor. We used to shout upstairs to ask him to join us, but as the door of his room is often closed and he's sometimes wearing headphones, that became quite the task. Everybody in our street knew that we were starting dinner before he did … 🙄

Looking for a fun solution to our problem, I stumbled upon Yo-Yo Machines. (A colleague shared the link in our company Slack.)

Yo–Yo Machines are playful communication devices that you can make yourself. They’re designed to fill a gap by letting people send one another nonverbal, expressive signals like lights, sounds or simple mechanical movements. We hope they’ll make it a little easier to feel close to our friends and families while we have to be physically separate.

I ordered the components online and set to putting them together. When it came to making the enclosures, I thought about doing something related to the ‘dinner time’ theme …

As a base for the enclosures I used two small Apple boxes: one from an Apple Magic Mouse and one from a set of AirPods. They're both quite a good fit for the breadboard assembly.

All the components inside the Apple Magic Mouse box.

The enclosure that we use in the kitchen is pretty standard: it has the mini solenoid inside the box to produce the knocks. I decorated it with a bell icon to refer to what happens upstairs when you knock it.

The enclosure for my son's room is a bit more elaborate. I thought it would be fun to have a little butler to tell our son that his dinner is served.

All of the breadboard assembly sits inside the AirPods box except for the mini solenoid. Here it's not supposed to knock the side of the box as with a ‘regular’ Knock-Knock box. Instead I want to use it to to tap a little bell.

I used a lasercutter to cut the parts of the (penguin) butler as a contraption to hold the mini solenoid and the bell.

The penguin sits on top of the AirPods box.

The solenoid is hidden behind the penguin.

Now we just knock on the box in the kitchen when we want our son to come down. He can acknowledge by knocking on the penguin‘s ‘plinth’.


Any questions or suggestions? You can find me on Twitter.