I designed this Arduino-powered printed wearable for Adafruit.
This project was requested by Adafruit as an easy introduction to 3d printing printing and casting. All of the custom components for this project are printed on a consumer-grade 3d printer sans support material. Even the mold that generates the glowy crystals prints in that same batch, making the project very easy to set up for first time printers. The knuckle ring contains a Li-Po, a Power Backpack, a Trinket Pro for the brains, and three Neopixels.
You can follow the tutorial to replicate one for yourself on Adafruit, and download the source files on Thingiverse.