Step 2: Cut your hat open
Be sure to decide whether you want to have your LED bulb face out when the hat is rolled up, or if you'll want to wear it without rolling (like in the photo). Cut a small (I mean absolutely tiny) hole for your led to fit through. Poke the two legs of the LED through the fabric of the hat, then bend them to feed them through to the inside of the hat, where you can access them from the cut that you have made in the edge of the hat. The legs of the LED also provide an anchor for the bulb, helping to keep it in place.