A lighting device circuit comprising: a reference LED string, a mirror LED string coupled in parallel to the reference LED string, an operational amplifier based current mirror circuit coupled to the reference LED string and to the mirror LED string, and a window comparator circuit that includes only a single input that is coupled to a fault sense node. The fault sense node directly connects to a drain node of a transistor within the operational amplifier based current mirror and a LED within the mirror LED string.

An airfield runway lamp controller is described herein. One airfield runway lamp controller includes a current sense transformer configured to detect a failure of a light source of an airfield runway lamp, and an alternating current (AC) switch configured to shunt the light source of the airfield runway lamp upon the current sense transformer detecting a failure of the light source.

A lighting system includes a first luminaire and a second luminaire which are arranged in an illumination area, and a controller. The first luminaire is connected to a first receiver which receives a signal from a transmission tag, and has a first lighting lamp. The second luminaire is connected to a second receiver which receives a signal from the transmission tag, and has a second lighting lamp. The controller turns on the first lighting lamp when the first receiver receives the signal from the transmission tag, then, turns on the second lighting lamp when the second receiver receives the signal from the transmission tag, and notifies that an abnormal situation has occurred when no signal from the transmission tag is received by the first receiver within a predetermined time period from the turning on of the second lighting lamp.

A device (1) for detecting a problem in or near a load (2, 3) coupled to a cable (6) of a cable system comprises an analyzing part (11) for analyzing a waveform of a cable signal for feeding the load (2, 3) and a deciding part (12) for in response to an analysis result deciding whether a problem in or near the load (2, 3) is present or not. The load (2, 3) may be coupled to the cable (6) via a driver (4, 5). The problem in or near the load (2, 3) may result in the driver (4, 5) amending a value of the waveform at or near a crest or a trough of the waveform. The analysis result may define whether the waveform has been amended by more than a threshold or not. The amending of the value of the waveform at or near the crest or the trough may comprise a positive pulse added to a crest or a negative pulse added to a trough.

This disclosure describes systems and techniques for managing streetlights. The subject matter included in this document is embodied in a method that includes receiving, at a computing device, information representative of a location and status of a streetlight included in a network of streetlights. The method also includes presenting a representation of the streetlight in a graphical user-interface in accordance with the received location and status information, and receiving information representing a selection of the streetlight for inclusion in a group of streetlights from the network. The method further includes initiating delivery of one or more control signals to the group of streetlights.

A control system for a hybrid machine is provided. The control system includes a controller communicably coupled to an energy storage unit of the hybrid machine. The controller is configured to receive data from the energy storage unit. The controller is configured to evaluate a current storage charge state of the energy storage unit based on the received data. The controller is configured to receive historical data related to idle events associated with an engine of the hybrid machine. The controller is configured to receive data related to one or more machine operating parameters. The controller is configured to pre-emptively control at least one of an engine speed and an engine power based on the received data for at least one of shutting down the engine during an idle state and restarting the engine.

A fault detection system (100) for detecting faulty devices among a first plurality of serviceable devices (200) is provided. The serviceable devices have a wireless transmitter (210) arranged to periodically transmit a wireless signal (230) that encodes a device identifier. Mobile devices have a receiver (310) arranged to receive the wireless signal of a serviceable device within the transmission range, and to obtain the device identifier from the wireless signal. A fault detector (400) is arranged to detect faulty devices by selecting device identifiers in the plurality of device identifiers for which no device identifier was received in a time period.

A system and method provide fail-safe operation of a lighting system. A lighting level detector is used to obtain a baseline lighting level for a low-intensity light. If the detector measures less than the baseline level when an occupancy sensor determines the space is unoccupied, a high-intensity light is energized and an indication is provided to a user that the low-intensity light has failed. A method provides daylighting operation of a lighting system. An occupancy sensor can have Wi-Fi functionality to enable remote configuration of the sensor. A line voltage occupancy sensor can include an interface with low voltage devices. An occupancy sensor can include an integral interface to enable an external control system to override the sensor's normal logic under emergency conditions. An occupancy sensor can include an active temperature compensation feature. An occupancy sensor can also incorporate an automatically adjustable coverage area.

An exterior aircraft light unit includes a power input coupleable to an aircraft on-board power supply; at least one LED coupled to the power input for receiving power from the aircraft on-board power supply and configured to emit a light output; an optical sensor arranged for sensing an intensity detection portion of the light output and configured to output a detection signal indicative of an intensity level of the light output; an end of life detector, coupled to the optical sensor for receiving the detection signal and configured to determine an end of life condition; and a fuse circuit coupled to the end of life detector; wherein the fuse circuit is configured to irreversibly disable an LED circuit board upon the end of life detector communicating the end of life condition to the fuse circuit.

The invention relates to a method for operating a first and a second light-emitting unit of a motor vehicle. A first voltage converter is provided for operating the first light-emitting unit. A second voltage converter is provided for operating the second light-emitting unit. A switching unit is arranged between the two light-emitting units and the voltage converters, such that the second voltage converter is connected to the first light-emitting unit.