Abstract: Devices, systems, and methods for providing smoke detectors are described herein. One smoke detector of a fire sensing system includes a circuit board body, having a set of front scattering emitting light sources located on one side of an optical chamber, a receiver of front scattering light beams from the front scattering emitting light sources and backward scattering light beams, and a set of backward scattering emitting light sources located between the set of front scattering emitting light sources and the receiver, the backward scattering light beams emitted from the backward scattering emitters.

Abstract: Devices, systems, and methods for providing point heat detectors based on surface mounted thermistors are described herein. One circuit board for a point heat detector of a fire sensing system includes a circuit board body having number of corners, at least one hole provided in the circuit board body proximate to one of the corners, and a surface mounted thermistor mounted on at least one corner.

Abstract: An optical smoke detector includes a radiant energy source and a sensor. The source and the sensor are carried by an optical block that provides a fixed orientation therebetween and barriers therebetween. The barriers reduce noise and false alarming due to bugs, dust, water vapor, and other intrusive elements. The barriers can include V-shaped members at a selective angle relative to center lines of the source and the sensor.

Abstract: An optical smoke detector includes a radiant energy source and a sensor. The source and sensor are carried by an optical block which provides a fixed orientation therebetween and barriers therebetween. The barriers reduce noise and false alarming due to bugs, dust water vapor and other intrusive elements. The barriers can include V-shaped members at a selective angle relative to center lines of the source and sensor.