Meet the SunSprite: a solar powered sun exposure tracker that tracks UV exposure and prevents sunburn. It provides you with useful feedback based on your personal data. The device syncs with your iPhone automatically. You never have to charge it as the device is completely solar-powered.
SunSprite has dual sensors to measure visible and UV light, so your body gets just the right amount of exposure. It has 10 LEDs, each standing for 10% of your goal. You can attach SunSprite to your clothes easily. Sets you back $149 at this time.