Devices, methods, and systems for a self-calibrating fire sensing device are described herein. One device includes a first transmitter light-emitting diode (LED) configured to emit a first light, a second transmitter LED configured to emit a second light, a first photodiode on-axis with the first transmitter LED, wherein the first photodiode is configured to select a first gain or a second gain of a first variable gain amplifier and detect an LED emission level of the first light responsive to selecting the first gain and detect a scatter level of the second light responsive to selecting the second gain, a second photodiode on-axis with the second transmitter LED, wherein the second photodiode is configured to select a third gain or a fourth gain of a second variable gain amplifier and detect an LED emission level of the second light responsive to selecting the third gain and detect a scatter level of the first light responsive to selecting the fourth gain, and a controller configured to recalibrate the fourth gain responsive to the detected LED emission level of the first light and recalibrate the second gain responsive to the detected LED emission level of the second light.

Devices, methods, and systems for a self-calibrating fire sensing device are described herein. One device includes an adjustable particle generator and a variable airflow generator configured to generate aerosol having a particular particle size and optical scatter properties at a controllable density level, a first transmitter light-emitting diode (LED) configured to emit a first light that passes through the aerosol, a second transmitter LED configured to emit a second light that passes through the aerosol, a photodiode configured to detect a scatter level of the first light that passes through the aerosol and detect a scatter level of the second light that passes through the aerosol, and a controller configured to calibrate a gain of the photodiode based on the detected scatter level of the first light, the detected scatter level of the second light, and the controllable aerosol density level.

Devices, methods, and systems for a self-calibrating fire sensing device are described herein. One device includes an adjustable particle generator and a variable airflow generator configured to generate aerosol having a particular particle size and optical scatter properties at a controllable density level, a first transmitter light-emitting diode (LED) configured to emit a first light that passes through the aerosol, a second transmitter LED configured to emit a second light that passes through the aerosol, a photodiode configured to detect a scatter level of the first light that passes through the aerosol and detect a scatter level of the second light that passes through the aerosol, and a controller configured to calibrate a gain of the photodiode based on the detected scatter level of the first light, the detected scatter level of the second light, and the controllable aerosol density level.

A smoke detection device main body of a portable smoke detector can switch smoke detection sensitivity. At the start of operation, the smoke detection sensitivity of the portable smoke detector is equal to or higher than a smoke detection sensitivity of a fixed smoke detector that detects smoke in a monitoring area. At this time, switching of smoke detection sensitivity does not work. After the fixed smoke detector detects smoke generation, when the portable smoke detector is used to locate the smoke generation position while moving in the monitoring area, an operation is performed from an initial sensitivity. When a predetermined smoke detection signal is detected while using the portable smoke detector to identify the smoke generation position, the smoke detection sensitivity switching is activated, and the smoke detection sensitivity is changed accordingly. By lowering the smoke detection sensitivity, the smoke generation position is narrowed down and identified.

Devices, methods, and systems for a self-calibrating fire sensing device are described herein. One device includes a first transmitter light-emitting diode (LED) configured to emit a first light, a second transmitter LED configured to emit a second light, a first photodiode on-axis with the first transmitter LED, wherein the first photodiode is configured to select a first gain or a second gain of a first variable gain amplifier and detect an LED emission level of the first light responsive to selecting the first gain and detect a scatter level of the second light responsive to selecting the second gain, a second photodiode on-axis with the second transmitter LED, wherein the second photodiode is configured to select a third gain or a fourth gain of a second variable gain amplifier and detect an LED emission level of the second light responsive to selecting the third gain and detect a scatter level of the first light responsive to selecting the fourth gain, and a controller configured to recalibrate the fourth gain responsive to the detected LED emission level of the first light and recalibrate the second gain responsive to the detected LED emission level of the second light.

Devices, methods, and systems for a self-calibrating fire sensing device are described herein. One device includes a first transmitter light-emitting diode (LED) configured to emit a first light, a second transmitter LED configured to emit a second light, a first photodiode on-axis with the first transmitter LED, wherein the first photodiode is configured to select a first gain or a second gain of a first variable gain amplifier and detect an LED emission level of the first light responsive to selecting the first gain and detect a scatter level of the second light responsive to selecting the second gain, a second photodiode on-axis with the second transmitter LED, wherein the second photodiode is configured to select a third gain or a fourth gain of a second variable gain amplifier and detect an LED emission level of the second light responsive to selecting the third gain and detect a scatter level of the first light responsive to selecting the fourth gain, and a controller configured to recalibrate the fourth gain responsive to the detected LED emission level of the first light and recalibrate the second gain responsive to the detected LED emission level of the second light.

A smoke detection device main body of a portable smoke detector (10) can switch smoke detection sensitivity. At the start of operation, the detection smoke sensitivity of the portable smoke detector is equal to or higher than a detection sensitivity of smoke in a fixed smoke detector (100) that detects smoke in a monitoring area. At this time, switching of smoke detection sensitivity does not work. After the fixed smoke detector detects smoke generation, when the portable smoke detector is used to locate the smoke generation position while moving in the monitoring area, an operation is performed from an initial sensitivity. When a predetermined smoke detection signal is detected while using the portable smoke detector to identify the smoke generation position, the smoke detection sensitivity switching will be activated, and then the smoke detection sensitivity will be changed accordingly. By lowering, the smoke generation position is narrowed down and identified.

The automatic adjustment of audio alert characteristics of an alert device using ambient noise levels is described. In one aspect of the invention, a machine-readable medium has executable instructions to cause a machine to perform a method to receive an audio sample of ambient noise and adjust a characteristic of the audio alert, such as, the volume level of the audio alert, based on the ambient noise level.

The automatic adjustment of audio alert characteristics of an alert device using ambient noise levels is described. In one aspect of the invention, a machine-readable medium has executable instructions to cause a machine to perform a method to receive an audio sample of ambient noise and adjust a characteristic of the audio alert, such as, the volume level of the audio alert, based on the ambient noise level.

A smoke detector dynamic range adjustment system includes a light emitting element for emitting light at a plurality of light output levels, the plurality of light output levels automatically adjusted by a controller when a saturation limit is approached. The system also includes a light receiving element for receiving light emitted from the light emitting element.