These cufflinks from Adafruit Industries are made of machined aluminum to look like the power button on an Apple computer. Â Inside the cufflinks are tiny circuit boards and LEDs. Â Insert a battery in each before wearing, and the power symbol will glow with a pulsing light for 24 hours. Â The source code, circuit board files, schematics, and CAD files are posted on GitHub, so you can modify them as you like.
The Gadgeteer
