Abstract: A smoke detector and a chamber are provided. The chamber includes a bottom plate, top plate, a plurality of baffle ribs disposed between the bottom plate and top plate, a transmitter base disposed between the bottom plate and top plate, and a receiver base disposed between the bottom plate and top plate. The receiver base is arranged apart from the transmitter base, and a center point of the chamber, being taken as an apex, the receiver base, and the transmitter base jointly define an angle being in a range of 45 degrees to 65 degrees.

Abstract: A smoke detecting device includes a main body, a light-emitter, a first light-receiver, and a second light-receiver. The main body includes a smoke detecting chamber formed therein. The light-emitter is located within the smoke detecting chamber. The first light-receiver is located within the smoke detecting chamber. An optical axis of the first light-receiver and an optical axis of the light-emitter cooperatively define a first scattering angle there-between. The second light-receiver is located within the smoke detecting chamber. An optical axis of the second light-receiver and an optical axis of the light-emitter corporately define a second scattering angle there-between. The second light-receiver is closer to the light-emitter than to the first light-receiver. The second scattering angle is smaller than the first scattering angle.