RADIO-BASED ALERT AND INFORMATION SYSTEM FOR EMERGENCY AND NORMAL OPERATIONS USING EXISTING WI-FI INFRASTRUCTURE

Abstract

The paper addresses the design and practical implementation of a local automated radio-based voice alert and information system for emergency and routine situations using the existing network infrastructure of an educational institution. The relevance of the study is determined by the need to ensure timely, synchronized, and reliable notification of people inside educational buildings under increased safety requirements, as well as by restrictions on the use of certain external digital services. The proposed approach focuses on centralized voice alerting that does not depend on personal user devices.

The system is based on a client–server architecture with centralized control of audio streams at the server level and the use of distributed end radio point devices. The server side is implemented using the open-source AzuraCast platform, which provides audio stream generation, routing, and broadcasting, supports priority alert modes, automated notification scenarios, and scheduled playback. The use of standard streaming protocols enables stable operation of the system within a local network without reliance on third-party cloud solutions.

End alert devices are implemented on the ESP32 microcontroller platform using the I2S digital audio interface and the MAX98357A digital-to-analog converter with a Class D amplifier. This hardware configuration ensures compact size, energy efficiency, and high interference immunity of the client modules. The paper describes the implementation of automated air-raid alert notifications based on the open API of the alerts.in.ua service and the AzuraCast API, as well as the support of scheduled information modes. The practical performance of the proposed system has been confirmed through testing in an educational institution.

Keywords: alert system, voice notification, radio system, Wi-Fi infrastructure, ESP32, AzuraCast, automation.