Development and Performance Analysis of an IoT-Based Automatic Irrigation System for Chili Plants

Abstract

Efficient irrigation management is important for maintaining suitable soil moisture conditions for chili plant growth while reducing unnecessary manual intervention. This paper presents the development of an Internet of Things (IoT)-based automatic irrigation system using an ESP32 microcontroller, soil moisture sensors, a DHT22 temperature sensor, a relay module, and water pumps. Sensor measurements are transmitted through Wi-Fi to the Blynk IoT platform for real-time monitoring and manual override. A preliminary cultivation experiment was conducted using three chili plants maintained under three target soil-moisture regimes: 81–100%, 60–80%, and 30–50%. The observed results showed that the plant maintained within the 60–80% range achieved the highest recorded vegetative growth, reaching 57 cm by Week 9, and the largest recorded fruit length of 5.5 cm during Weeks 13–17. These observations suggest that the moderate moisture regime was more favourable than the wetter and drier regimes in this preliminary experiment. However, because only one plant was used for each moisture condition and no independent control group or inferential statistical analysis was included, the findings should be interpreted as preliminary rather than statistically generalizable. The prototype demonstrates the feasibility of threshold-based IoT irrigation for small-scale chili cultivation and provides a basis for future replicated field experiments.