In summer time it is easy to get burned by sun especially on the beach. It is hard to track when sun is too active or when to stop sunbathing. To keep things right it is better to use a sunburn alarm which measures sunlight UV intensity level.
Prototybe is based on Propeller Platform SD along with LCD UI module. There is no need for some expensive UV light sensors – they used simple UV LED connected backwards – this way sensed wavelength is equal to generated light. Alarm also encounters skin type, sunscreen if used – these are entered before starting device. Be safe and have fun!