UV rays are invisible everywhere. Every year, many people develop skin cancer, which can be prevented by regularly applying sun cream or other precautions. The prototype of a wearable bracelet in combination with an App warns the user if the UV rays and protection are insufficient and should be extended. During my exchange semester at HKU (Hogeschool voor de Kunsten Utrecht), I developed a smart device in the Experimental Society module that is designed to warn users of excessive UV radiation.