https://terra-docs.s3.us-east-2.amazonaws.com/IJHSR/Articles/volume7-issue7/IJHSR_2025_77_23.pdf

Various IoT-based systems have been developed to guide people to evacuate buildings during emergencies like fires.However, research on environments where the internet is disrupted or the radio wave conditions are poor is insufficient.This study proposes an IoT-based system for guiding safe evacuations, utilizing both internet-based communication and a fallback audible sound wave mode for disruptions.This study presents an IoT-based evacuation guidance system that operates via MQTT and switches to sound-based communication when the internet fails.It receives digitally encoded emergency data through the internet or building sound broadcast systems and minimizes transmission by storing the building layout and calculating optimal evacuation paths using Dijkstra's algorithm.The system utilizes 18 kHz and 19 kHz audio frequencies with FFT (Fast Fourier Transform) and BFSK (Binary Frequency Shift Keying) modulation for sound wave communication.The test was conducted in a simulated school environment, where the system successfully guided users to exits during emergencies, including scenarios with network disruptions.Additionally, a noise interference test was performed to assess the robustness of sound wave communication.Results indicate that the proposed system effectively guides evacuation with minimal data transmission and maintains functionality during internet disruptions, showcasing its potential for enhanced emergency response systems.