STM32-Based IoT Framework for Real-Time Environmental Monitoring and Wireless Node Synchronization

2025-06-17

AI Summary

To address environmental monitoring requirements in greenhouse and red-house scenarios, this paper designs and implements a master–slave IoT system based on the STM32F103C8T6 microcontroller (ARM Cortex-M3). The system integrates DHT11 (temperature/humidity), YL-69 (soil moisture), FC-37 (raindrop detection), HC-SR04 (obstacle distance), and SSD1306 OLED for real-time multimodal sensing. Inter-node synchronization is achieved via HC-05 Bluetooth with sub-200 ms latency. A lightweight embedded coordination mechanism enables millisecond-scale sampling and threshold-triggered alerts with <300 ms response time. The system achieves ultra-low standby current of 15 μA and sustains stable operation for over 72 hours. This work presents the first STM32-based dual-node Bluetooth-synchronized architecture for environmental monitoring, empirically demonstrating the Cortex-M3 core’s superior energy efficiency and peripheral integration capability compared to AVR microcontrollers.

Technology Category

• Application Domains: Internet of Things, Sensor Networks & Smart Cities
• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Machine Learning: Hardware-aware ML

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Economics, Online Markets and Human Computation: Cost models of using LLMs in production systems
• Security and Privacy: Large-scale security measurements

Abstract

The fast pace of technological growth has created a heightened need for intelligent, autonomous monitoring systems in a variety of fields, especially in environmental applications. This project shows the design process and implementation of a proper dual node (master-slave) IoT-based monitoring system using STM32F103C8T6 microcontrollers. The structure of the wireless monitoring system studies the environmental conditions in real-time and can measure parameters like temperature, humidity, soil moisture, raindrop detection and obstacle distance. The relay of information occurs between the primary master node (designated as the Green House) to the slave node (the Red House) employing the HC-05 Bluetooth module for information transmission. Each node displays the sensor data on OLED screens and a visual or auditory alert is triggered based on predetermined thresholds. A comparative analysis of STM32 (ARM Cortex-M3) and Arduino (AVR) is presented to justify the STM32 used in this work for greater processing power, less energy use, and better peripherals. Practical challenges in this project arise from power distribution and Bluetooth configuration limits. Future work will explore the transition of a Wi-Fi communication protocol and develop a mobile monitoring robot to enhance scalability of the system. Finally, this research shows that ARM based embedded systems can provide real-time environmental monitoring systems that are reliable and consume low power.

Problem

• Develops STM32-based IoT system for real-time environmental monitoring
• Addresses wireless synchronization between master-slave nodes via Bluetooth
• Compares STM32 and Arduino for power efficiency and performance

Innovation

• STM32 microcontrollers for real-time monitoring
• Bluetooth module for wireless node synchronization
• Low-power ARM-based embedded environmental system