Abstract: An ultraviolet light radiation sensing device to be wearable by a human being is provided, the device including a front part and a rear part, an ultraviolet light radiation sensor with associated microprocessor on a printed circuit board, a battery, and a wireless communication unit, e.g. for Bluetooth communication. If the front and rear part are made from a metal or metal alloy, and are interconnected by a middle member made from electrically insulating polymer material, the front and rear parts constitute antenna elements of the wireless communication unit. The device is intended to enable interaction with application data of a smartphone, a method being provided to establish recommended UV-dose and related exposure time by the sun onto the skin of the human being.