Implementation of an intelligent edge-computing fire security system: Integrating multi-sensor fusion, dual-source power redundancy and real-time IoT cloud telemetry

Cloud-dependent Internet of Things (IoT) fire detection prototypes have demonstrated that wireless sensor networks and mobile notification pipelines can shorten the gap between ignition and human awareness. However, single-microcontroller designs that rely on rigid threshold logic, a single mains or battery power rail, and one Wi-Fi communication path remain vulnerable to the very conditions a fire produces: power interruption, network congestion, and ambiguous sensor readings that trigger nuisance alarms. This study presents the design, implementation, and bench evaluation of an intelligent edge-computing fire security system that addresses these three vulnerabilities concurrently. A multi-sensor fusion front end, comprising digital temperature/humidity, catalytic gas/smoke, and infrared flame sensing, feeds a lightweight on-device classification routine running on an ESP32-S3 microcontroller, so that fire-likelihood decisions are computed locally rather than waiting on a round trip to the cloud. A dual-source power subsystem pairs a mains-fed, buck-regulated rail with a solar-charged lithium-ion battery and an automatic power-path switchover circuit, allowing the node to continue sensing, fusing, and alerting through grid outages. A communication layer publishes fused readings and alerts over MQTT to a cloud broker and mirrors critical events to a Firebase-backed mobile application, while a GSM module provides a Short Message Service (SMS) fallback when the primary wireless path is degraded or unavailable. Bench testing under simulated normal, hazardous, power-loss, and connectivity-loss scenarios indicates that on-device fusion reduces nuisance alarms relative to single-threshold logic, that the power subsystem switches sources within a sub-second window, and that the system sustains alert delivery through both communication paths. The system is presented as a low-cost, field-deployable extension of earlier cloud-only IoT fire alarm prototypes, contributing to United Nations Sustainable Development Goals 9 and 11 through resilient smart-building safety infrastructure.