Control network for led-based lighting system in a transit vehicle

Abstract

A transit vehicle lighting system has a plurality of LED-based lighting fixtures for providing interior illumination. A control network comprises a plurality of slave nodes for controlling the LED-based lighting fixtures, and a master node for controlling the slave nodes. The master node may be connected to the slave nodes by a combined power/communication bus in a daisy chain fashion. The slave node may include a power regulator and a controller for providing a target current command to the power regulator, and may adjust the target current based upon temperature measurements or a recorded age of the LEDs. An optical sensor may provide automatic dimming. A reduced number of LEDs may be used in an emergency mode. The lighting fixture may include a ceiling panel fixture and a riser panel attachable by way of a hinge mechanism.

What is claimed is: 
     
         1 . A lighting system for a transit vehicle, comprising:
 a plurality of LED-based lighting fixtures, each of said LED-based lighting fixtures comprising a plurality of light-emitting diodes (LEDs) collectively providing area lighting, and a plurality of slave nodes for controlling operation of the LEDs;   a master node for controlling said slave nodes and thereby controlling the operation of said LED-based lighting fixtures;   a power bus interconnecting said master node and slave nodes; and   a communication bus interconnecting said master node and slave nodes.