Design and Implementation of an IoT-Based Automatic Monitoring and Watering System for Eggplant Plants

Abstract

This study aims to design and implement an Internet of Things (IoT)-based monitoring and automatic watering system for eggplant (Solanum melongena L.) plants using a NodeMCU ESP8266 as the main controller. The system integrates a soil moisture sensor and a DHT11 temperature-humidity sensor to acquire real-time environmental data, which are transmitted to the Blynk cloud platform for remote monitoring. When the soil moisture level drops below a 50% threshold, a 5V mini water pump is automatically activated through a relay module until the optimum moisture level is restored. A CD4051 multiplexer is employed to allow multiple soil moisture sensors to share a single analog pin on the microcontroller, improving scalability for multi-plant applications. Based on the test results, the DHT11 sensor achieved an average accuracy of 99.2% compared with a reference digital thermometer, while the automatic pump consistently activated within 3-4 seconds once the soil moisture fell below the threshold, with an average data synchronization delay of 1-2 seconds between the NodeMCU and the Blynk platform. Therefore, this system can serve as an effective and efficient smart-farming solution for small-scale eggplant cultivation.