A system allowing a user of a browser program on a computer connected to an open distributed hypermedia system to access and execute an embedded program object. The system has, at each user end, an input unit used to input control signals for controlling and selecting the interactive media applications, and an output unit used to display an appropriate user-specific user interface. Events may also be re-annotated to reflect new or different capabilities of the EMS. Said PWM DC voltage is then applied to a WLED driver for driving a WLED. Due to its compact size, the photo sensor can be arranged in linear or two-dimensional manner for the realization of line and area sensors.