UV light

I'm a bit of a flashlight hoarder. Bike lights, work lights, EDC lights, head lamps, even night vision ... I have far too many, but try as I might, I can't seem to get rid of them.

Scientists have developed a fully transparent skin sensor that accurately measures UV radiation, detecting light and converting it to electrical signals. So before the sun's rays reach damaging levels, a phone alert lets users know it's time to cover up.