Mobile speaking duration monitor for auditorium, e.g. for conference use, has projected optical display using varying number of different color light sources to indicate elapsed time within respective lecture time segments

摘要

The duration monitor has an autonomous energy supply (3) and a programmable control unit (5) for generating and displaying an optical signal via different color light sources (9), indicating at least 3 different time segments. The display (6) has several light sources arranged in close proximity for each color, the overall number activated indicating the elapsed time within the time segment, an imaging device (7) projecting the display onto a display surface visible to the auditorium.