This project is a derivative of Morgan Stewart's Circuit Playground Yoyo (Watch her demo it on Adafruit's Show & Tell). In this remix, we'll encase a single Circuit Playground board and a lipo battery in 3D printed parts to make a yoyo. The NeoPixel LEDs can shine through the cover, making cool glowy effects. Most of the yoyo parts are 3D printed, and no hardware (machine screws, hex nuts, etc) are required. They feature threads that allow the pieces to be twisted together.
A yo-yo (also spelled yoyo) is a toy which in its simplest form is an object consisting of an axle connected to two disks, and a length of string looped around the axle, similar to a slenderspool. It is played by holding the free end of the string known as the handle (usually by inserting one finger into a slip knot) allowing gravity or the force of a throw to spin the yo-yo and unwind the string (similar to how a pullstring works), then allowing the yo-yo to wind itself back to one's hand, exploiting its spin (and the associated rotational energy). This is often called "yo-yoing". First made popular in the 1920s, yo-yoing remains a popular pastime of many generations and cultures. It was first invented in ancient Greece.
This is a fun project but in not intended to replace a professional yoyo. Because a yoyo relies on perfect balanced weight, it can be challenging to evenly distribute the weight two both sides - That being said, it can be done. I personally was able to get it to sleep for about 2-3 seconds which allows enough time to do tricks like Rock The Baby.
We'll need just a few parts to build this project, most of which are available in the Adafruit shop. You'll need to source a yoyo string. Everything else is 3D printed.
Here are some tools and supplies that you'll need access to complete this project. If you don't have access to a 3D printer, you can send the STL files to 3DHubs.com