I recently got into “Karakuri” paper models. It is a pretty eco-friendly and cheap hobby, especially if I use the paper from the ads that come in the mail.
Karakuri puppets are traditional Japanese mechanized puppets or automata-for-fun. It became a thing in Japan after Europeans introduced clocks. I imagine the first Japanese engineer or person who opened a clock and saw all those cams and gears then thought of making something way more fun ;p
I got this book from amazon.
The book has neat scientific explanations of the different movements and where you can see them in the real world.
It shows some projects done by high-school students
There are tips and tricks for what material and tools to use for example, the type of glue, the kind of mat and so on.
There is also the instant gratification from having cutouts ready to assemble.
Here is my favorite so far:
Here is what is inside:
Adding a PI / motion sensor
I could add a motion sensor and connect this to a Raspberry PI. Once somebody gets close to the bear, the cams will rotate and the bear will do a peek-a-boo. However, I find it nice to just do a project without electronics for a change.