An illustrative example monitoring device includes a plurality of radiation sources that respectively emit a different type of radiation. At least one radiation detector is situated to detect radiation emitted the radiation sources and reflected off airborne particles. The radiation detector has a first sensitivity configured for detecting a concentration of the particles within a first range and a second sensitivity configured for detecting a concentration of the particles within a second, different range. A processor is configured to determine a ratio of the types of detected radiation, a type of the particles reflecting the detected radiation based on the ratio, and the concentration of the particles reflecting the detected radiation based on the first or second sensitivity.

Devices, methods, and systems for a self-testing fire sensing device are described herein. One device includes an adjustable particle generator and a variable airflow generator configured to generate an aerosol density level, an optical scatter chamber configured to measure a rate at which the aerosol density level decreases after the aerosol density level has been generated, and a controller configured to compare the measured rate at which the aerosol density level decreases with a baseline rate, and determine whether the self-testing fire sensing device requires maintenance based on the comparison of the measured rate at which the aerosol density level decreases and the baseline rate.

Devices, methods, and systems for a self-testing fire sensing device are described herein. One device includes an adjustable particle generator and a variable airflow generator configured to generate an aerosol density level, an optical scatter chamber configured to measure a rate at which the aerosol density level decreases after the aerosol density level has been generated, and a controller configured to compare the measured rate at which the aerosol density level decreases with a baseline rate, and determine whether the self-testing fire sensing device requires maintenance based on the comparison of the measured rate at which the aerosol density level decreases and the baseline rate.

A method for multiple sensor calibration and tracking, the method including identifying a non-permanent object in a first field of detection (FOD) of a sensor, wherein the sensor is one of a plurality of sensors positioned in various locations at a site, each sensor has a corresponding FOD; tracking the identified object by single-sensor tracking in the first FOD; predicting appearance of the object, and based on the predictions initiating single-sensor tracking in at least one other FOD where it is predicted that the object will appear; and outputting data captured from the tracked FODs.

In certain embodiments, continuous adjustment of a normal state of a sensor and reducing false positive floor sensor alerts may be facilitated. In some embodiments, wavelength readings may be continuously obtained from a floor sensor. A normal state of the floor sensor may be continuously adjusted based on wavelength readings that fail to satisfy upper and lower wavelength thresholds of the continuously adjusted normal state. An event may be detected when one or more wavelength readings from the floor sensor satisfy the upper or lower wavelength thresholds of the continuously adjusted normal state. A number of wavelength readings that satisfy the upper or lower wavelength thresholds may be determined. A suspicious activity alert may be generated when the number of wavelength readings satisfies a predetermined count threshold.

A vehicle includes determines that a vehicle alarm system has been engaged and determines a local context applicable to the vehicle alarm system. The vehicle obtains an alarm system configuration mapping applicable in light of the local context. The vehicle changes sensitivity of one or more sensors associated with the alarm system based on the configuration mapping.

A vehicle includes determines that a vehicle alarm system has been engaged and determines a local context applicable to the vehicle alarm system. The vehicle obtains an alarm system configuration mapping applicable in light of the local context. The vehicle changes sensitivity of one or more sensors associated with the alarm system based on the configuration mapping.

Use of multiple sensors to determine whether motion of an object is occurring in an area is described. In one aspect, an infrared (IR) sensor can be supplemented with a radar sensor to determine whether the determined motion of an object is not a false positive.

An illustrative example monitoring device includes a plurality of radiation sources that respectively emit a different type of radiation. At least one radiation detector is situated to detect radiation emitted the radiation sources and reflected off airborne particles. The radiation detector has a first sensitivity configured for detecting a concentration of the particles within a first range and a second sensitivity configured for detecting a concentration of the particles within a second, different range. A processor is configured to determine a ratio of the types of detected radiation, a type of the particles reflecting the detected radiation based on the ratio, and the concentration of the particles reflecting the detected radiation based on the first or second sensitivity.

Devices, methods, and systems for a self-testing fire sensing device are described herein. One device includes an adjustable particle generator and a variable airflow generator configured to generate an aerosol density level, an optical scatter chamber configured to measure a rate at which the aerosol density level decreases after the aerosol density level has been generated, and a controller configured to compare the measured rate at which the aerosol density level decreases with a baseline rate, and determine whether the self-testing fire sensing device requires maintenance based on the comparison of the measured rate at which the aerosol density level decreases and the baseline rate.