There are so many nice hacks in [Joekutz]’s retro LED display project that it’s hard to know where to start. There’s his DIY LED display controlled by an Arduino UNO.

How about a quick review. Here's how you make a UV light with a smart phone. Start with a smart phone that has an LED light (for the camera flash). You want two things from this light.

LED lights are the latest thing in home lighting, using less energy and lasting longer than their incandescent cousins. How do they work? Find out in the latest installment of Appliance Science.