Wow, it looks like there a lot of solar powered stuff that’s coming out lately. Check out this instructable that shows you how to make a solar powered bike helmet with night lights!
This project could be done in many different ways and I spent a lot of time trying different parts and ideas. The key breakthroughs for me were to use 3 AAA batteries, vs the 4AA’s that came with the Solar Panel because they were a better balance of weight to the right amount of power and milliamps. I ended up using a simple soft case Velcro wrapped to the helmet, and relied heavily on Black Shoe Goo! (I think it’s the new duct tape). Most of the work was getting an easy rapid prototype idea to work rain or shine, for months on end, and be versatile with replaceable parts. I kept it flat black because the helmet is flat black, so chips don’t show. And I’m in New York City, where black is the default color.