Abstract: There is provided a smoke detector including a first light source, a second light source surface, a light sensor and a processor. The light sensor receives reflected light when the first light source and the second light source emit light, and generates a first detection signal corresponding to light emission of the first light source and a second detection signal corresponding to light emission of the second light source. The processor distinguishes smoke and floating particles according to a similarity between the first detection signal and the second detection signal.

Abstract: A security revolving door assembly includes a revolving door and a controlling unit. The revolving door has a rotary vertical shaft, a vertical lateral wall extending circumferentially relative to the shaft, and a plurality of door wings extending radially from the shaft. The door wings have distal ends, include first and second door wings, are rotatable along with the shaft, and define with the lateral wall a trap space when the first and second door wings reach respectively first and second positions. The distal ends of the first and second door wings confront the lateral wall when the first and second door wings reach respectively the first and second positions. The controlling unit is operable so as to stop rotation of the door wings as soon as the door wings define the trap space.