Various embodiments of the teachings herein include a measurement chamber for a smoke detection unit of a smoke detector. The measurement chamber may include: at least a passage for smoke to be detected; and a measurement chamber cover with angular light trap structures on an inside of the measurement chamber. The angular light trap structures are shaped to follow the compact-design principle of a Fresnel stepped lens.

Various embodiments of the teachings herein include a measurement chamber for a smoke detection unit of a smoke detector. The measurement chamber may include: at least a passage for smoke to be detected; and a measurement chamber cover with angular light trap structures on an inside of the measurement chamber. The angular light trap structures are shaped to follow the compact-design principle of a Fresnel stepped lens.

A fire detection apparatus 1F for detecting a fire in a monitored area, the fire detection apparatus 1F being attached to an installation surface of an installation object, the fire detection apparatus 1F comprises a detection space 60F in which detection of a detection target is performed; an incidence suppressing unit that inhibits ambient light from entering the detection space 60F, the incidence suppressing unit being able to allow a gas containing the detection target to flow into and out of the incidence suppressing unit; an accommodating unit that accommodates the incidence suppressing unit, the accommodating unit being able to allow the gas to flow into and out of the accommodating unit; and a light shielding wall 140F provided to surround the incidence suppressing unit on an inside of the accommodating unit, wherein the incidence suppressing unit includes a first incidence suppressing unit that covers a part of the detection space 60F, and a second incidence suppressing unit provided on an installation surface side of the first incidence suppressing unit, the second incidence suppressing unit covering another part of the detection space 60F, and the light shielding wall 140F is configured such that the light shielding wall overlaps a boundary between the first incidence suppressing unit and the second incidence suppressing unit when viewed in a direction orthogonal to the installation surface.

A fire detection apparatus 1F for detecting a fire in a monitored area, the fire detection apparatus 1F being attached to an installation surface of an installation object, the fire detection apparatus 1F comprises a detection space 60F in which detection of a detection target is performed; an incidence suppressing unit that inhibits ambient light from entering the detection space 60F, the incidence suppressing unit being able to allow a gas containing the detection target to flow into and out of the incidence suppressing unit; an accommodating unit that accommodates the incidence suppressing unit, the accommodating unit being able to allow the gas to flow into and out of the accommodating unit; and a light shielding wall 140F provided to surround the incidence suppressing unit on an inside of the accommodating unit, wherein the incidence suppressing unit includes a first incidence suppressing unit that covers a part of the detection space 60F, and a second incidence suppressing unit provided on an installation surface side of the first incidence suppressing unit, the second incidence suppressing unit covering another part of the detection space 60F, and the light shielding wall 140F is configured such that the light shielding wall overlaps a boundary between the first incidence suppressing unit and the second incidence suppressing unit when viewed in a direction orthogonal to the installation surface.

Example implementations include a smoke detector comprising a smoke chamber; an LED that generates light in the smoke chamber; a photodetector configured to detect whether a threshold amount of light is scattered by smoke particles in the smoke chamber; and one or more self-testing components configured to re-direct the light from the LED toward the photodetector for self-testing the LED and the photodetector. Some further implementations include one or more masking self-test components configured external to the smoke chamber to direct light from outside the smoke chamber into the smoke chamber and toward the photodetector for determining whether the smoke detector has been masked. Some further example implementations include a method comprising controlling one or more self-testing components of a smoke detector to re-direct at least a portion of light from an LED toward a photodetector; and determining whether the photodetector causes an alarm trigger in response to the controlling.

Example implementations include a smoke detector comprising a smoke chamber; an LED that generates light in the smoke chamber; a photodetector configured to detect whether a threshold amount of light is scattered by smoke particles in the smoke chamber; and one or more self-testing components configured to re-direct the light from the LED toward the photodetector for self-testing the LED and the photodetector. Some further implementations include one or more masking self-test components configured external to the smoke chamber to direct light from outside the smoke chamber into the smoke chamber and toward the photodetector for determining whether the smoke detector has been masked. Some further example implementations include a method comprising controlling one or more self-testing components of a smoke detector to re-direct at least a portion of light from an LED toward a photodetector; and determining whether the photodetector causes an alarm trigger in response to the controlling.

A fire detection apparatus 1 includes a first light emitting unit 101 that irradiates a detection space located inside or outside the fire detection apparatus 1 with first detection light, a second light emitting unit 102 that irradiates the detection space with second detection light having a different wavelength from a wavelength of the first detection light, a light receiving unit 103 that receives scattered light of the first detection light irradiated from the first light emitting unit 101 due to smoke, outputs a first light receiving signal according to the received scattered light, receives scattered light of the second detection light irradiated from the second light emitting unit 102 with respect to smoke, and outputs a second light receiving signal according to the received scattered light, and an identification unit 107a that identifies a type of smoke present in the detection space on the basis of an output ratio of an output value of the first light receiving signal to an output value of the second light receiving signal output from the light receiving unit 103 and a rising rate of the output value of the first light receiving signal or the second light receiving signal.

Devices and methods for a sealed electrical connector are described herein. Some embodiments include a spring connecting a first PCB to a second PCB, wherein the spring includes a first end portion in contact with the first PCB, a second end portion in contact with the second PCB, and a middle portion extending between the first end portion and the second end portion, a spacer surrounding the middle portion of the spring, a first seal seated in a first groove of the spacer and in contact with the first PCB, and a second seal seated in a second groove of the spacer and in contact with the second PCB.

Devices and methods for a sealed electrical connector are described herein. Some embodiments include a spring connecting a first PCB to a second PCB, wherein the spring includes a first end portion in contact with the first PCB, a second end portion in contact with the second PCB, and a middle portion extending between the first end portion and the second end portion, a spacer surrounding the middle portion of the spring, a first seal seated in a first groove of the spacer and in contact with the first PCB, and a second seal seated in a second groove of the spacer and in contact with the second PCB.

A photoelectric smoke detector (14) connected to a signal line (12-1) drawn into a warning area from a receiver (10) transmits a fire signal including identification information of smoke caused in detection zones Z1 and Z2. In the detection zones, a sensor (18) for sensing a change of physical phenomenon other than smoke involved in fire is provided, and the sensor (18) is connected to the signal line (12-1) via a relay device (16). The sensor (18) is at least one of a CO.sub.2 sensor, a CO sensor, a fire sensor, and a heat sensor. A fire alarm control unit (48) of the receiver (10) causes an alarm to be given, when determining the identification information of the smoke by the photoelectric smoke detector (14) and a sensing value by at least one of the CO.sub.2 sensor, the CO sensor, the fire sensor, and the heat sensor.