Abstract: The present system provides a compact light diffusing and mixing structure for uniformly dispersing light at an exit surface, the apparatus having a light entrance surface which faces a light exit surface located on the opposite side of the light diffusing and mixing structure; a beam splitter light guide assembly located between the entrance and exit surface; a reflective surface located adjacent to the beam splitter light guide assembly. The light diffusing structure works such that light entering the entrance surface on striking the beam splitter light guide assembly is directed in part directly towards the exit surface and in part towards the reflective surface which in turn directs the light towards the exit surface and thereby evenly diffusing or dispersing the light across the exit surface. The system also provides a compact fast battery charger for Ni-MH and NiCAD batteries. The charger can indicate the degree of charge of the battery during a charging state and a discharging state.

Abstract: A surveillance fence comprising at least two posts (10) each equipped with electro-magnetic radiation transmitters (12) and receivers (14) which establish two parallel communications links. Each posts (10) communicate with a surveillance computer at a headquarters (20). Only one post (10) communicates directly via cables with headquarters (20). Data is transmitted over the communication links in opposite directions by modulating the electromagnetic energy beams. A message starts at headquarters (20) and is passed along post (10) to post (10) and back again to headquarters (20). Each post (10) can add information to the message as it is passed along. The interruption of the electromagnetic energy beams signals an intrusion whose location and time of occurence is recorded by a processor (16) which initiates an alarm. If a post (10) can not relay its intrusion data, the data is stored until the communications link is reestablished.