Abstract: 

The Fire Detection Alarm System circuit presented here uses a Flame Sensor, comparator IC LM393, and a relay. The Flame Sensor detects fire intensity, while the LM393 IC functions as a comparator. In the absence of fire, the flame sensor stops conducting, and the buzzer stays off. When fire is detected, the flame sensor starts conducting, activating the buzzer.

Application of the Circuit:
Most flame sensor-based circuits on the market require costly components and complicated circuitry. This circuit uses readily available flame sensors, reducing cost and complexity. The Fire Detection Alarm System circuit activates a buzzer upon detecting fire, providing continuous feedback.

Why This Particular Circuit:
The circuit operates on 5V DC and uses a Flame Sensor as the fire detector, making it cost-effective and reliable.

Explained Working of Circuit:
The IC LM393 is used as a comparator, processing the output from the flame sensor. In normal conditions, no fire is detected, and the buzzer stays off. When fire is detected, the buzzer activates. The relay serves as a switch to control the circuit’s operation.

Part List:

• Semiconductors:
  • U1 – LM393 (8-pin IC)
• Resistors (all 5% carbon unless specified):
  • R2 – 10k Ohm (variable)
  • R3 – 1k Ohm
  • R4 – 1k Ohm
  • R5 – 10k Ohm
  • R6 – 10k Ohm
• Capacitor:
  • C1 – 1uF
• Miscellaneous:
  • D4 – Flame Sensor
  • D1 – Red LED
  • D2 – Green LED
  • 5V USB Cable
  • Buzzer
  • Relay
  • PCB

Key Applications:

Used widely in electronic circuits, automation, robotics, and educational projects. Optimized for reliable performance in Indian environments.