A lighting device includes a multi-faceted heat sink with facets in a center portion facing outward. The user interface system of the preferred embodiments has been specifically designed to be incorporated into an electronic device, such as the display of a mobile phone, but may be incorporated in any suitable device that interfaces with a user in both a visual and tactile manner. The integrated circuit includes a digital signal processing chain, a random sequence generator coupled to an input of the digital signal processing chain, and a checksum calculator coupled to an output of the digital signal processing chain.