Design and Simulation of a Fire Alarm System Using Smoke and Temperature Sensors for Secondary Schools in Rivers State

Background: Fire incidents in Nigerian secondary schools have resulted in loss of life and destruction of property, often due to the absence of early warning systems. Electronic fire alarm systems using sensor fusion offer reliable, low-cost protection. Aim: This project designed and simulated a fire alarm system integrating smoke and temperature sensors for deployment in secondary schools in Rivers State, South South Nigeria. Methods: An MQ-2 smoke sensor and an LM35 temperature sensor were interfaced with an ATmega32 microcontroller. When sensor readings exceeded preset thresholds, the system activated a buzzer alarm and triggered an SMS alert via a GSM module. Circuit design and simulation were performed in Proteus 8.0. A prototype was subsequently constructed and bench-tested. Results: The system reliably detected smoke concentrations above 300ppm and temperatures exceeding 55 degrees Celsius. Alert triggering latency was 1.2 seconds. False alarm rate in controlled testing was 2.1%. The SMS alert feature successfully transmitted notifications to a predefined mobile number. Conclusion: The designed fire alarm system is reliable, affordable, and appropriate for secondary school safety applications. Recommendations include field deployment trials and integration with school management notification systems. Keywords: fire alarm, smoke sensor, temperature sensor, secondary schools, Rivers State.