Fire & Smoke Alarm with Buzzer Alert

Problem statement

Small labs, stores and server rooms often lack low-cost fire detection systems, increasing risk of late response to fire accidents.

Abstract

The project is a basic fire and smoke alarm system using gas/smoke sensors and temperature sensors. When smoke concentration or temperature crosses preset limits, a microcontroller or simple comparator circuit activates a buzzer and warning LED. It can be mounted near electrical panels, labs or storerooms to provide an early warning.

Components required

• Smoke/gas sensor (e.g. MQ-2 or MQ-6)
• Temperature sensor (e.g. LM35 / thermistor)
• Small microcontroller or comparator circuit
• Buzzer
• Red and green LEDs with resistors
• Power supply module
• PCB and wiring

Block diagram

Working

The smoke sensor output voltage increases with smoke concentration while the temperature sensor reports ambient temperature. The control circuit samples both readings and compares them with thresholds. If either value indicates danger, it turns on the buzzer and warning LED. A green LED indicates safe conditions. Sensitivity can be adjusted using preset potentiometers.

Applications

• Basic fire safety in labs and stores
• Kitchen or hostel corridor monitoring
• Mini project for sensor interfacing
• Educational display in safety awareness events