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.

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.

Various embodiments include a scattered light smoke detector comprising: a two-color LED for emitting light of a first wavelength and a second wavelength; a photosensor spectrally matched with said two-color LED; and a control unit connected to the two-color LED and to the photosensor. The control unit is configured to control the two-color LED to emit light of the first wavelength or the second wavelength and to detect a photosensor signal of the photosensor. The control unit is further configured to analyze the photosensor signal for a first scattered radiation intensity and a second scattered radiation intensity allocated respectively to the first wavelength and the second wavelength. There is a polarizer optically connected upstream of the photosensor or downstream of the two-color LED. The polarizer polarizes light passing through at different intensities in dependence upon the respective wavelength of said light.

Various embodiments include a scattered light smoke detector comprising: a two-color LED for emitting light of a first wavelength and a second wavelength; a photosensor spectrally matched with said two-color LED; and a control unit connected to the two-color LED and to the photosensor. The control unit is configured to control the two-color LED to emit light of the first wavelength or the second wavelength and to detect a photosensor signal of the photosensor. The control unit is further configured to analyze the photosensor signal for a first scattered radiation intensity and a second scattered radiation intensity allocated respectively to the first wavelength and the second wavelength. There is a polarizer optically connected upstream of the photosensor or downstream of the two-color LED. The polarizer polarizes light passing through at different intensities in dependence upon the respective wavelength of said light.

Analog signal measurement and related circuitry, systems, and methods are disclosed. Circuitry includes timing circuitry configured to assert a first enable signal at a first time and a second enable signal at a second time. The circuitry also includes an operational amplifier circuit configured to enable responsive to the assertion of the first enable signal. The operational amplifier circuit is configured to receive an analog input signal and, if enabled, generate an amplified analog input signal responsive to the analog input signal. The circuitry further includes signal analyzing circuitry configured to enable responsive to the assertion of the first enable signal, compare the amplified analog input signal to one or more threshold values responsive to the assertion of the second enable signal, and generate an alert signal responsive to a determination that the amplified analog input signal falls outside of the one or more threshold values.

A heat sensor includes a base and a heat sensor body. The base is to be mounted onto a mounting surface of a building. The heat sensor body has a bottomed cylindrical shape and is to be attached to the base. The heat sensor body includes an opening, a board, a heat detection unit, and at least one wall member. The at least one wall member controls flow of a gas to cause the gas that passed through the opening to flow toward the heat detection unit. The at least one wall member separates the flow of the gas that has entered the heat sensor body from an external space through the opening into a plurality of gas flows and directs one of the plurality of gas flows, which has been separated to flow beside an inner surface of the heat sensor body, toward the heat detection unit.

The present invention relates to a system for testing the availability of a detector for detecting smoke. More specifically, the present invention relates to a detector with a testing unit arranged to detect whether the detector has been covered, such that it is unable to perform its function as a smoke detector.

The present invention relates to a system for testing the availability of a detector for detecting smoke. More specifically, the present invention relates to a detector with a testing unit arranged to detect whether the detector has been covered, such that it is unable to perform its function as a smoke detector.

A fire detection apparatus 1A includes a detector cover 70A for inhibiting ambient light from entering a detection space 60A, an inner cover 30A that accommodates the detection space 60A and the detector cover 70A, an outer cover 20A that accommodates the inner cover 30A, a first opening 30aA provided in a side portion on an opposite side from a side portion on an installation surface side among side portions of the inner cover 30A, a second opening provided in a side portion on an opposite side from a side portion on an installation surface among side portions of the detector cover 70A, and a flat plate-shaped insect screen 50A provided on the detector cover 70A and configured to substantially cover the entire second opening.