Fertilizer Management System for A Compact Hydroponic Planter

摘要

Liquid fertilizer management system for a compact hydroponic planter was developed. An EC (Electro Conductivity) sensor that calculates nutrient concentration value with a high accuracy with an error rate of 8.4 % by introducing an op-amp oscillator and an EC curved surface generated by the weighted least-squares method. A fertilizer addition device feeds stock solution to the planter by controlling air pressure of a pump to adjust the EC to a target value. Precise control of 1.7-% variance was achieved under various conditions. In total, our system can manage the EC with an error rate of 10 %.