Temperature and Humidity Control in a Small-Scale Greenhouse in a Tropical Climate

Global climate change has increased fluctuations in temperature and humidity, threatening the sustainability of the agricultural sector. This research aimed to develop an Internet of Things (IoT)-based microclimate control system for greenhouses using Arduino and the Thingspeak platform. The system was designed as a closed-loop using an ESP-32 as the control center, a DHT-22 sensor for data acquisition, and Solid-State Relay (SSR) actuators to control the blower, heater, and misting pump. Testing was conducted in a greenhouse with an area of 3 m² and a height of 2.3 meters. The results showed that the system could maintain a temperature of 27–36°C (external deviation: 29–48°C) and humidity of 85–90% (external deviation: 47–100%) with low overshoot, namely 1.18% (temperature) and 1.49% (humidity), and a settling time of under 4 minutes. The steady-state error was within the tolerance limit (maximum 5%). However, the system experienced a data loss of 26.04% and an average transmission delay of 16.5 seconds due to network instability at the test location. Nevertheless, the system proved effective in maintaining an optimal microclimate for small-scale plant growth.