Energy efficient control of polychromatic solid-state lighting using a sensor network

Motivated by opportunities in smart lighting, energy efficiency, and ubiquitous sensing, we present the design of polychromatic solid-state lighting controlled using a sensor network. We developed both a spectrally tunable light source and an interactive lighting testbed to study the effects of systems that adjust in response to changing environmental lighting conditions and users' requirements of color and intensity. Using both linear and nonlinear optimization, the setpoints of overdetermined systems (greater than three wavelengths) and the energy consumption of the network are adjusted according to the room's lighting conditions (e. g., lux and color temperature of multiple fixtures). Using these techniques, it is possible to maximize luminous efficacy or the color rendering index for a given intensity and color temperature. We detail the system modeling, design, optical calibration, and control theory required to modulate the luminous output and minimize wasted energy.