Design of control system for water quality monitoring system for hydroponics application

Abstract

In hydroponic farming, optimal pH value is important to regulate nutrient availability for efficient plant growth. This study aims to design an autonomous pH monitoring and control system for maintaining an optimal pH range. The prototype was developed for data acquisition, data processing and data visualization to ensure that the measured nutritional solution parameters are within the specified range: temperature (18–35°C), pH (5.5–8.0), and dissolved oxygen level (>2 ppm). Data collected at sampling rate of 10 seconds utilising temperature sensor, pH sensor, and dissolved oxygen sensor were processed using a microcontroller on a Node-RED interface in a Raspberry Pi. The processed data were stored in InfluxDB before being displayed in Grafana. If the value exceeded the threshold, a Telegram alert was delivered to the end-user. The pH data were used to build a framework to control the pH levels within range. Two peristaltic pumps (DFRobot, DFR0523) were utilized to pump potassium hydroxide or phosphoric acid solution if the pH was out of range. The developed prototype was able to automatically control the pH within the optimum range in the nutrient solution, which will positively impact the nutrient adsorption and subsequent plant growth in a hydroponics system.