Real-Time Closed-Loop Color Control of a Multi-Channel Luminaire Using Sensors Onboard a Mobile Device

Smart homes and Internet of Things are emerging concepts in modern society, with intelligent lighting being an important part of it. Besides providing visual satisfaction through its color-rendering properties, lighting also has other effects on human well-being. In order to exploit the full potential of a smartly lit home, lighting systems need to be equipped with accurate controllers that can control the spectrum and color characteristics of light in addition to conventional ON-OFF and dimming control. However, current commercial smart lighting products with such capabilities need to employ expensive sensors which are still lacking in terms of closed-loop feedback which is imperative for accurate color control of light-emitting diode (LED)-based luminaires. This paper presents a novel approach that uses the camera available on modern smartphones to perform closed-loop color control for lighting systems in smart homes. The algorithm is able to perform multi-channel mixing for any color and also white light at a desired correlated color temperature with high color-rendering index. This approach proves to be very economical and convenient as no external sensors are required and can be performed using any Android smartphone on a compatible LED-based luminaire.