Design and Implementation of a Human-Machine-Interface Based Hydroponic Nutrient Solution Irrigation System

摘要

This study aims to develop a human-machine-interface (HMI) based nutrient solution regulation system, which can be applied to hydroponic cultivation of plants. The proposed system includes a personal computer, microcontrollers, flow-meter modules, water quality monitor modules (pH, EC, and DO), ion electrode sensing modules (potassium, calcium, magnesium, etc.), peripheral circuit, power modules, pipe, nutrient solution storage tank, and liquid-regulating valve. The flow rates of five different nutrient solutions are controlled by a microcontroller which regulates the flow control valves. The user can select the desired plant name on the HMI or program the concentrations of nutrient solutions manually, which results in an automatic deployment of nutrient solution for a particular plant (by default, five different compositions of plant nutrient solutions are provided in the database). Meanwhile, the concentrations of nutrient solutions in the cultivation bed are displayed in real-time in the HMI. The experiment was conducted in a cultivation bed (120 cmx 60 cm x 11 cm (LxWxH)) equipped with a light emitting diode (LED) lighting board. The results demonstrate that a range of tolerable concentrations of nutrient solutions can be maintained by using the proposed system.