Abstract: An ambient light sensor measures an ambient light level at one point in an illuminated environment, such as a warehouse, office, shop, cold-storage facility, or industrial facility, and provides an indication of the measured ambient light level to a processor. The processor maps the measured ambient light level to an estimated ambient light level at a different point in the illuminated environment from the measured ambient light level (e.g., a “task height” about three feet from a warehouse floor). The processor may determine the difference between the estimated ambient light level and a desired light level at the task height, and may change the artificial illumination provided by a light fixture to make the actual ambient light level at task height match the desired light level at the task height.

Abstract: Light-emitting diodes (LEDs) generate light more efficiently than high-intensity discharge lamps or high-intensity fluorescent lamps. Driving a series of LEDs with a constant-voltage primary supply and a low-voltage LED driver keeps efficiency high. Unfortunately, LED forward voltage varies as a function of temperature: at low temperature, the forward voltage rises. Placing the LEDs in series magnifies the forward voltage increases. This makes it difficult to drive a series of LEDs at low temperature with a constant-voltage supply because the forward voltage can exceed the power supply voltage. To account for this behavior, an exemplary LED lighting fixture includes a “bypass” circuit that, when engaged, effectively removes at least one LED from each series string of LEDs to bring the total forward voltage below the power supply voltage. The low-voltage driver circuit monitors temperature, and engages the “bypass” circuit when necessary to ensure that DC voltage is not exceeded.

Abstract: Light-emitting diodes (LEDs) generate light more efficiently than high-intensity discharge lamps or high-intensity fluorescent lamps. Driving a series of LEDs with a constant-voltage primary supply and a low-voltage LED driver keeps efficiency high. Unfortunately, LED forward voltage varies as a function of temperature: at low temperature, the forward voltage rises. Placing the LEDs in series magnifies the forward voltage increases. This makes it difficult to drive a series of LEDs at low temperature with a constant-voltage supply because the forward voltage can exceed the power supply voltage. To account for this behavior, an exemplary LED lighting fixture includes a “bypass” circuit that, when engaged, effectively removes at least one LED from each series string of LEDs to bring the total forward voltage below the power supply voltage. The low-voltage driver circuit monitors temperature, and engages the “bypass” circuit when necessary to ensure that DC voltage is not exceeded.

Abstract: An ambient light sensor measures an ambient light level at one point in an illuminated environment, such as a warehouse, office, shop, cold-storage facility, or industrial facility, and provides an indication of the measured ambient light level to a processor. The processor maps the measured ambient light level to an estimated ambient light level at a different point in the illuminated environment from the measured ambient light level (e.g., a “task height” about three feet from a warehouse floor). The processor may determine the difference between the estimated ambient light level and a desired light level at the task height, and may change the artificial illumination provided by a light fixture to make the actual ambient light level at task height match the desired light level at the task height.

Abstract: An ambient light sensor measures an ambient light level at one point in an illuminated environment, such as a warehouse, office, shop, cold-storage facility, or industrial facility, and provides an indication of the measured ambient light level to a processor. The processor maps the measured ambient light level to an estimated ambient light level at a different point in the illuminated environment from the measured ambient light level (e.g., a “task height” about three feet from a warehouse floor). The processor may determine the difference between the estimated ambient light level and a desired light level at the task height, and may change the artificial illumination provided by a light fixture to make the actual ambient light level at task height match the desired light level at the task height.

Abstract: Light-emitting diodes (LEDs) generate light more efficiently than high-intensity discharge lamps or high-intensity fluorescent lamps. Driving a series of LEDs with a constant-voltage primary supply and a low-voltage LED driver keeps efficiency high. Unfortunately, LED forward voltage varies as a function of temperature: at low temperature, the forward voltage rises. Placing the LEDs in series magnifies the forward voltage increases. This makes it difficult to drive a series of LEDs at low temperature with a constant-voltage supply because the forward voltage can exceed the power supply voltage. To account for this behavior, an exemplary LED lighting fixture includes a “bypass” circuit that, when engaged, effectively removes at least one LED from each series string of LEDs to bring the total forward voltage below the power supply voltage. The low-voltage driver circuit monitors temperature, and engages the “bypass” circuit when necessary to ensure that DC voltage is not exceeded.

Abstract: An ambient light sensor measures an ambient light level at one point in an illuminated environment, such as a warehouse, office, shop, cold-storage facility, or industrial facility, and provides an indication of the measured ambient light level to a processor. The processor maps the measured ambient light level to an estimated ambient light level at a different point in the illuminated environment from the measured ambient light level (e.g., a “task height” about three feet from a warehouse floor). The processor may determine the difference between the estimated ambient light level and a desired light level at the task height, and may change the artificial illumination provided by a light fixture to make the actual ambient light level at task height match the desired light level at the task height.

Abstract: A teleconferencing bridge simulates the auditory spatial ambience of a face-to-face conference. This bridge uses a novel binaural approach to simulate spatial ambience.