Smoke detector

The present invention relates to systems and methods for detecting smoke. Smoke detectors detect the presence of smoke particles as an early indication of fire. Smoke detectors are used in closed structures such as houses, factories, offices, shops, ships, aircraft, and the like. Smoke detectors may include a chamber that admits a test atmosphere while blocking ambient light. A light receiver within the chamber receives a level of light from an emitter within the chamber, which light level is indicative of the amount of smoke contained in the test atmosphere. A smoke detector includes a housing defining a dark chamber admitting test atmosphere. A light receiver is disposed within the chamber. A scatter emitter is positioned within the chamber such that light strikes the receiver when reflected off particles suspended in the test atmosphere. An obscuration emitter is positioned within the chamber such that light emitted is directed to the receiver unless obstructed by particles suspended in the test atmosphere. A smoke detect signal is generated responsive to a measurement made responsive to the scatter emitter and/or the obscuration emitter.