Create a Simple Waterproof Bike Light From Two Bottle Caps
If you enjoy cycling around the city , especially at night, you need to be sure to get noticed. This small DIY light turns on automatically when you ride your bike and is very easy to make.
This light is useful for more than just cycling. Basically, it’s a small, bright, cheap, water-resistant, bottle-cap sized flashlight that you can stick on anything. All you need is a couple of small electronics and a bunch of junk from around the house (like a bottle of soda, a can of soda, an old tree branch, and a few screeds). You don’t even need to know how to solder, so this is a great project for little beginners.
Check out the full instructions on the MAKE website for how to do this.