Abstract

The Internet of Things (IoT) enables real-time environmental monitoring through interconnected sensor systems. This paper presents a low-cost, modular, and scalable IoT-based weather station for capturing temperature, humidity, barometric pressure, rainfall, and light intensity. The system uses Arduino/STM32 microcontrollers, DHT11, MPX4115, LDR, and rain sensors. Data is wirelessly transmitted to the Blynk Cloud via the ESP8266 module and displayed on a mobile app dashboard. Key contributions include circuit simulation, firmware logic, PCB design, and an in-depth comparison with seven recent studies. The proposed solution demonstrates reliability, affordability, and feasibility for real-world deployment.