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 measurementsor 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 distributed control network for a transit vehicle lighting system, comprising:
 a plurality of LED-based lighting fixtures, each of said LED-based lighting fixtures comprising a plurality of light-emitting diodes (LEDs) for illuminating an area of a transit vehicle;   a plurality of slave nodes for controlling the LED-based lighting fixtures;   a master node in communication with said slave nodes; and   a digital communications bus for communicating among the master node and the slave nodes.