L’Oreal and John Rogers built a thumbnail-sized UV sensor
L'Oreal is not a name that you'd normally associate with CES, but the cosmetics giant is now a regular exhibitor at the show . This year, the company is demonstrating a thumbnail-worn smart device that's less than two millimeters thick. UV Sense is a battery-free electronic sensor that's designed to monitor your sun exposure and, with the help of an NFC-enabled smartphone, help limit your skin cancer risk. UV Sense is a big leap from L'Oreal's last offering, My UV Patch , which was just a sticker loaded with a series of dyes. These dyes changed color depending on how long they've been exposed to light, and users could track the changes by taking pictures with the corresponding app. This time around, the sensor is designed to be worn more than once, and will store up to three months' worth of data at a time. Would-be owners can affix the sensor to their thumbnail -- where, apparently, you get optimal sunlight exposure -- for up to two weeks. Then, the...