This study aims to determine the optimal level of illumination in a classroom based on the intensity of incoming light and the number of people who were in the room so it is can to save electricity use and can produce a lighting system in accordance with SNI. In designing this simulation using fuzzy inference systems with Tsukamoto method as engineering calculations and there are three variables that are modeled, namely: the intensity of light, the number of people, and the level of illumination. Variable light intensity is assumed by the membership function Less, Enough, and More. While variable number of membership functions are assumed by Little, Medium, and Many. For
variable illumination levels assumed by the membership function Low, Dim, and Bright. Exemplified fuzzy rules used there are 9 rules.
The results showed that in order to determine the optimal level of lighting in a room can be fuzzy inference system tsukamoto method. Results of the simulation design using arduino.