Summary I've always been a little nervous about riding my longboard around in the dark, so I decided to create a dynamic light for the back of my helmet. It is an extremely simple circuit. I hooked up an Adafruit Neo Pixil Ring and connected it to a Trinket. Other than that it is a li-po battery and an on/off switch. Everything is hot glued on so it is semi-permanent. All the code for the trinket and a wiring diagram can be found at - Here's a video of it in action. - Instructions Print on the standard setting in MakerWare.