Modeling of Fuzzy Logic Control System for Controlling Homogeneity of Light Intensity from Light Emitting Diode

The use of Light Emitting Diode (LED) as the lighting device becomes popular due to its energy-efficient characteristic. However, LED has radiation angle that is relatively smaller than other types of lighting device. This results in heterogeneity of light intensity that received by particular point near the LED. To obtain homogeneity of light intensity, this paper proposes a model of fuzzy logic control system to control illumination of LEDs lamp in a room. This model involves several components, namely LEDs lamp, LED driver, illumination sensor, microcontroller, and a differential transceiver RS-485. The fuzzy logic control system that used in this model uses error of illumination and delta error of illumination as input parameter. As output, this control system will change duty cycle of Pulse Width Modulation (PWM) that used to control illumination of LEDs lamp. Based on experiment result, when expected light intensity is set to 150 Lux, homogeneity of light intensity can be achieved with error less than 2%. In addition, the control system also can reduce energy consumption up to 40% under the experimental environment.