Smoke detectors and smoke alarms are provided which have one or more light shields configured to block or minimize the transmission of ambient light to their light receivers. Light shield configurations for facilitating such functionality are provided as well. The shield/s include a material which attenuates a majority amount of light within a particular range of light that a light source of the smoke detector may be configured to only emit and/or the range of light the light receiver may configured to only convert to photocurrent. In some cases, the shield/s surrounds the light source and/or the light receiver arranged external to an interior chamber of the smoke detector. In some cases, the shield/s may at least partially span a connection side of an external housing of the smoke detector. Alternatively, the shield may be arranged in a space between the interior chamber and the connection side of the housing.

An air filtration for detecting hazardous particles includes a housing having an air flow pathway extending therethrough. The housing is configured to receive air flow from an inlet of the housing and to expel air flow from an outlet of the housing. A pair of electrodes are positioned within the air flow pathway. A sensor system is operatively connected to the pair of electrodes to measure electrical current flowing therebetween. A processor is operatively connected to the sensor system to compare the measured electrical current with a stored baseline current. An alarm is operatively connected to the processor. The processor activates the alarm when the measured electrical current is different than the stored baseline current.

An air filtration for detecting hazardous particles includes a housing having an air flow pathway extending therethrough. The housing is configured to receive air flow from an inlet of the housing and to expel air flow from an outlet of the housing. A pair of electrodes are positioned within the air flow pathway. A sensor system is operatively connected to the pair of electrodes to measure electrical current flowing therebetween. A processor is operatively connected to the sensor system to compare the measured electrical current with a stored baseline current. An alarm is operatively connected to the processor. The processor activates the alarm when the measured electrical current is different than the stored baseline current.

The invention relates to a forest fire early detection system and/or forest fire risk analysis system with a sensor unit and an evaluation unit for analyzing the measured signals supplied by the sensor unit, the sensor unit having a signal source for emitting a signal, which signal source is suitable and intended for passing a signal into a nearby test specimen, as well as a method for forest fire early detection and/or forest fire risk analysis.

The invention relates to a forest fire early detection system and/or forest fire risk analysis system with a sensor unit and an evaluation unit for analyzing the measured signals supplied by the sensor unit, the sensor unit having a signal source for emitting a signal, which signal source is suitable and intended for passing a signal into a nearby test specimen, as well as a method for forest fire early detection and/or forest fire risk analysis.

As an example, an apparatus may include: an ionization chamber, a voltage source to drive the ionization chamber; a voltage sensor to measure an ionization chamber output voltage; a calibration circuit to compensate the ionization chamber output voltage based on a correction factor; and a monitoring circuit to trigger an alarm if the compensated output voltage meets a predetermined condition. The calibration circuit may determine the correction factor to compensate for any leakage current affecting the ionization chamber output voltage.

As an example, an apparatus may include: an ionization chamber, a voltage source to drive the ionization chamber; a voltage sensor to measure an ionization chamber output voltage; a calibration circuit to compensate the ionization chamber output voltage based on a correction factor; and a monitoring circuit to trigger an alarm if the compensated output voltage meets a predetermined condition. The calibration circuit may determine the correction factor to compensate for any leakage current affecting the ionization chamber output voltage.

This application is directed to a method of home monitoring and control implemented by a doorbell installed at a door of a home, an application executable by a monitoring device, and a remote server. The doorbell has a button that, upon being touched, depressed or activated, wirelessly causes an audio speaker of an electronic device to sound an audible notification and/or a message to be sent to a monitoring device associated with an occupant of the home to indicate presence of a person at the door. The doorbell also has a camera that captures video data within a field of view. The remote server receives the video data from the doorbell and relays them to the monitoring device. The application receives and displays at least a portion of the video data captured by the camera.

This application is directed to a home monitoring and control system including a doorbell installed at a door of a home, an application executable by a monitoring device, and a remote server. The doorbell has a button configured to, upon being touched, depressed or activated, wirelessly cause an audio speaker of an electronic device to sound an audible notification or a message to be sent to the monitoring device to indicate presence of a person at the door. The doorbell also has a camera configured to capture video data within a field of view. The remote server is configured to receive from the doorbell the video data and the message, and relay them to the monitoring device. The application is configured to receive and display at least a portion of the video data captured by the camera of the doorbell.

This patent specification relates to a wall switch that comprises a docking station and a user-removable wall-switch head unit. In some embodiments, the docking station is configured to receive the user-removable wall-switch head unit, and configured to be permanently connected to a wall and coupled to high-power voltage wires. In some embodiments, the user-removable wall-switch head unit is configured to be user-insertable into said docking station and user-removable therefrom such that the user is not exposed to high-voltage connections when inserting or removing. In some embodiments, the wall switch controller further comprises inputs and outputs and circuitry for switchably controlling household line current power to a household electrical fixture. In some embodiments, the wall switch controller further comprises an occupancy sensor, a temperature sensor, or a processor.