Intelligent multi-coloured lighting system design with fuzzy logic controller

Abstract

This thesis is about design of an intelligent energy efficient lighting system based on fuzzy logic controller that uses multi-colour LEDs to produce light of the required luminance level and appropriate colour in a typical room space. The lighting system incorporates automatic controlling of a room’s window shade opening, conveniently harvesting daylight. Appropriate room occupancy sensors were set to dim off the LEDs if there are no people in the room. A movement sensor was also considered for dimming the LEDs if the persons in the room are asleep. A colour sensor or decoder was included in the control system to dim off the LEDs if the colour signal is not initiated. The colour decoder signal determine the LEDs’ output light colour, and close the window shades if the required room’s light colour is not white. Two Fuzzy Logic controllers were used in the system; the first one to control opening of the room’s window shades, and the other to control the LEDs’ output luminance level. The study was limited to simulation of the design in a MATLAB software environment. However, a proposal of the appropriate hardware that could be used to actualize the lighting system was also researched and a labeled block diagram for the same provided. The appropriate devices were identified, configured and assembled into a complete operating simulate system using a MATLAB-Simulink applications software. The designed system was simulated in the computer MATLAB environment, and the results were observed and monitored using the associated Simulink scopes. The LEDs were observed (via current pulse width) to dim accordingly in response to level of illumination in the room; the higher the outdoor light into room, the smaller the luminance from the LEDs. If outdoor light is very low, the window shade was observed to close. Also observed was the window shade closing when the LEDs output light colour is not white. The simulated model was able to calculate accurately the respective primary colour-part ratios, where the values were used in driving the RGB LEDs for production the required room lighting colour. The designed multi-coloured LED lighting system model is intelligent in saving lighting electric energy, and providing room illumination levels and lighting colour requirements