This article reviews the application of the Internet of Things (IoT) in agriculture using Arduino UnoR3. The authors, from various universities in Indonesia, aim to explore the potential of IoT in the Indonesian agricultural sector, which is a crucial part of the national economy. The study uses a literature review method to analyze scientific works and provides an overview of IoT applications in agriculture, aiming to enhance productivity and quality of agricultural outputs. The introduction highlights the importance of agriculture in human life and the need for technological advancements to improve efficiency and ease of tasks. IoT is discussed as a key technology that can connect various devices through the internet, making processes more convenient. The authors mention several previous studies on IoT in agriculture, including those using Raspberry Pi and Telegram bots, but this study focuses on Arduino UnoR3. The article then details several IoT applications in agriculture: 1. **Smart Irrigation**: A system that monitors and controls irrigation activities, such as water flow, air temperature, and rainfall, to optimize water supply and reduce manual labor. 2. **Humidity and Temperature Control**: A system for monitoring and controlling humidity and temperature in mushroom cultivation using sensors and microcontrollers. 3. **Soil Fertility Detection**: A system that uses sensors to detect soil pH and moisture levels, providing real-time data to farmers. 4. **Automated Plant Watering**: A system that uses sensors to monitor soil moisture and temperature, and automatically water plants based on predefined conditions. 5. **Soil Moisture and Rainfall Monitoring**: A system that monitors soil moisture and rainfall, providing data to help farmers make informed decisions about fertilization and irrigation. The article concludes that IoT applications in agriculture offer significant benefits, including increased efficiency, reduced manual labor, and improved decision-making. The authors suggest that further research and innovation in IoT technology can lead to more advanced and effective solutions for the agricultural sector.This article reviews the application of the Internet of Things (IoT) in agriculture using Arduino UnoR3. The authors, from various universities in Indonesia, aim to explore the potential of IoT in the Indonesian agricultural sector, which is a crucial part of the national economy. The study uses a literature review method to analyze scientific works and provides an overview of IoT applications in agriculture, aiming to enhance productivity and quality of agricultural outputs. The introduction highlights the importance of agriculture in human life and the need for technological advancements to improve efficiency and ease of tasks. IoT is discussed as a key technology that can connect various devices through the internet, making processes more convenient. The authors mention several previous studies on IoT in agriculture, including those using Raspberry Pi and Telegram bots, but this study focuses on Arduino UnoR3. The article then details several IoT applications in agriculture: 1. **Smart Irrigation**: A system that monitors and controls irrigation activities, such as water flow, air temperature, and rainfall, to optimize water supply and reduce manual labor. 2. **Humidity and Temperature Control**: A system for monitoring and controlling humidity and temperature in mushroom cultivation using sensors and microcontrollers. 3. **Soil Fertility Detection**: A system that uses sensors to detect soil pH and moisture levels, providing real-time data to farmers. 4. **Automated Plant Watering**: A system that uses sensors to monitor soil moisture and temperature, and automatically water plants based on predefined conditions. 5. **Soil Moisture and Rainfall Monitoring**: A system that monitors soil moisture and rainfall, providing data to help farmers make informed decisions about fertilization and irrigation. The article concludes that IoT applications in agriculture offer significant benefits, including increased efficiency, reduced manual labor, and improved decision-making. The authors suggest that further research and innovation in IoT technology can lead to more advanced and effective solutions for the agricultural sector.