Patent ID: 9013317
Filing Date: 2015-04-21
Classification: G08B

Abstract:
1. An optical smoke detector comprising: a housing having a base configured for attaching said detector to a surface, and a cover having a side wall and a bottom wall defining an interior of said cover; an optical sensor for generating a signal representative of detected light; and a control circuit for controlling operation of the detector; wherein: said control circuit includes a plurality of temperature sensors for sensing a rise in ambient temperature caused by a fire and generating a signal representative thereof, and wherein said control circuit is configured to adjust the sensitivity of the optical sensor in dependence on a comparison of said representative signal from the temperature sensors with a reference value and in dependence on a comparison of voltage and rate of change of voltage of said representative signal from the temperature sensors to change the threshold at which smoke is detected; said temperature sensors are located above an internal surface of said bottom wall within the housing and are substantially equally spaced; and said control circuit is configured to compare said signal representative of detected light with a reference signal and generate an alarm signal in dependence thereon.