A Spectrally Tunable Smart LED Lighting System With Closed-Loop Control

Light emitting diodes (LEDs), with their ability to produce tunable light spectrums, present a significant opportunity to improve on existing lighting systems. They can be applied to smart and specialized lighting, which can be highly beneficial in the residential, commercial, and industrial sectors. In this paper, we present a novel closed-loop control algorithm with feedback from a spectral sensor, which allows the light output spectrum to converge toward a target spectrum. The control system was experimentally validated by the hardware implementation of a wireless smart lighting system with the eight tunable LED channels with different dominant wavelengths (450-650 nm) designed to cover a large portion of the visible light spectrum. Experimental results show a near perfect replication of target spectra, with an accuracy within 5% for the correlated color temperatures and Euclidean distances which fall well within a five-step u'v' unit circle.