A rail signal arrangement for a rail signaling system comprises a rail signal having a rail signal lamp including a plurality of light emitter sub-arrays each comprising a light emitter, wherein the light emitter sub-arrays are electrically connected in parallel. A control circuit is provided and configured to operate the rail signal lamp in response to operating instructions from a remote operations management system, detect the proportion of light emitter sub-arrays that are in an operable condition with a monitoring system, and provide a condition status signal to the remote operations management system in accordance with whether the proportion of light emitter sub-arrays in an operable condition meets a minimum threshold level.

A method for operating a light emitting diode arrangement with at least one light emitting diode includes the steps of: a) determining at least one instantaneous current-voltage value pair; b) matching the instantaneous current-voltage value pair with an original current-voltage value pair; and c) determining an updated current feed based on the matching and driving the light emitting diode with the updated current feed.

A method for operating a light emitting diode arrangement with at least one light emitting diode includes the steps of: a) determining at least one instantaneous current-voltage value pair; b) matching the instantaneous current-voltage value pair with an original current-voltage value pair; and c) determining an updated current feed based on the matching and driving the light emitting diode with the updated current feed.

A method of determining operating conditions of an exterior aircraft light comprising at least one light source includes: operating the at least one light source of the exterior aircraft light; repeatedly detecting light with a light detector, which is located at the exterior aircraft light and configured for providing light detection values; determining a smallest light detection value (I.sub.min) provided by the light detector within a first period of time, and storing said smallest light detection value (I.sub.min) as an element of a series of smallest light detection values (I.sub.min); and evaluating the light detection values and the series of smallest light detection values (I.sub.min) for detecting erosion of an optical component of the exterior aircraft light, for detecting the presence of ambient light and/or for detecting the presence of fog and/or clouds in front of the exterior aircraft light.

A luminosity intensity monitoring system for maintaining compliance with a regulated level of visibility of specific-purpose lighting systems. The luminosity intensity monitoring system may be compatible with both incandescent and LED-based lighting systems, and may incorporate “smart” technology built into a luminaire or separately installed circuitry, and may be installed as original equipment or configured for retro-fit applications. The luminosity intensity monitoring system may be configured to present an early visible or audible warning which may indicate the visibility of a luminaire may be at risk of being non-compliant with regulations set forth by convention or civil authority. Methods for monitoring luminosity intensity are provided, whereby if the luminosity intensity of a luminaire approaches or falls below a predetermined threshold, or a luminaire approaches or exceeds a predetermined duration of service, the luminosity intensity monitoring system may present a visible warning signal, or an audible warning signal, or combinations thereof.

A grow light system for growing plants. The grow light system can have a carrier board assembly containing a plurality of apertures and a plurality of LED modules and secondary LED modules removably engaged with the carrier board in the apertures and forming a gap between LED module and the carrier board. The grow light system can be configured to draw air through the gap over the LEDs and along the heat sink fin to reduce the temperature of the LED module. A plurality of the LED modules can be connected in series and the carrier board can include a dedicated receptacle for a single LED module that is not connected in series with the remaining LED modules.

A grow light system for growing plants. The grow light system can have a carrier board assembly containing a plurality of apertures and a plurality of LED modules and secondary LED modules removably engaged with the carrier board in the apertures and forming a gap between LED module and the carrier board. The grow light system can be configured to draw air through the gap over the LEDs and along the heat sink fin to reduce the temperature of the LED module. A plurality of the LED modules can be connected in series and the carrier board can include a dedicated receptacle for a single LED module that is not connected in series with the remaining LED modules.

A system and method to determine a health status of a LED light string. The system (100) includes a circuit that includes a LED light string (110) and a pulsed current driver (115) of the LED light string. The circuit is connected to a power source (105). The system includes a current sensor (120) measuring a current through the circuit. The system includes a detecting device (130) determining a state of the circuit. The detecting device determines an expected current expected to be passing through the circuit where the expected current is associated with the state. The detecting device receives a current measurement from the current sensor during a time when the circuit is in the state. The detecting device determines a comparison between the current measurement and the expected current. The detecting device generates an output indicative of a health status of the circuit based on the comparison.

A system and method to determine a health status of a LED light string. The system (100) includes a circuit that includes a LED light string (110) and a pulsed current driver (115) of the LED light string. The circuit is connected to a power source (105). The system includes a current sensor (120) measuring a current through the circuit. The system includes a detecting device (130) determining a state of the circuit. The detecting device determines an expected current expected to be passing through the circuit where the expected current is associated with the state. The detecting device receives a current measurement from the current sensor during a time when the circuit is in the state. The detecting device determines a comparison between the current measurement and the expected current. The detecting device generates an output indicative of a health status of the circuit based on the comparison.

An artificial grow environment system includes a luminaire, a constant current LED driver, a first light sensor, a hemispherical incident and translucent light housing, a second light sensor isolated from all light and a circuit configured to supply 0 to 10 VDC to the dimming input of the constant current LED driver such that the LED light is linearly dimmed, from full-on to full-off, in inverse proportion to an amount of ambient light received by the first light sensor as temperature-compensated in accordance with data collected by the second light sensor. The luminaire includes a light shield housing at least one LED light. The first light sensor, surrounded by a hemispherical incident, translucent light housing, is coupled to the light shield and separated from the LED light so as to be isolated from the LED light and receive ambient light in the artificial grow environment.