Design of closed-loop feedback control system for mini greenhouse illumination based on PWM

Because of the illumination adjustment problem of seedling cultivation in mini greenhouse, a closed-loop feedback control system is proposed to control illumination based on PWM in this paper. This system is composed of single chip, buck circuit, PWM circuit based on DC-DC, LED, feedback circuit of illumination collection, and LCD1602 display circuit. In order to achieve intelligent adjustable light source, The single chip output adjustable PWM to control the current strength to control the led illumination, and The illumination is instantaneously fed back to the single chip via a light sensor for processing to meet the different illumination requirements of each growth stage of the plant. The system proves that the design can solve the illumination control problem in mini greenhouse, and it has real-time feedback and adjustment function.