ThinkGeek’s UV Monkey is a small keyring gadget that will assist you by checking UV levels so that you know when to charge solar devices and and when to go indoors to protect your skin. Once exposed to sunlight, the center will change to different shades of purple to indicate increasing levels of UV light (darker means a higher level of UV).
Gadgeteer Comment Policy - Please read before commenting
I love these things! I just wish they would “ding” to let you know when you’ve been out too long… sometimes it is easy to forget to look at a meter.
(I am imagining a Meredyth scale turkey timer in my head)
I have had frisbees made out of a similar material. They take only handful of seconds to change color, so it really wouldn’t be useful as a “Meredyth Timer.”