Fire Alarm System

Fire Alarm System

The Fire Alarm System works on the principle of optical smoke detection. It uses a light source (bulb) and a Light Dependent Resistor (LDR) to detect smoke. When smoke particles interrupt the light path, it changes the resistance of the LDR, triggering an alarm.

Hardware Explanation:

1. Bulb (9V):
   Acts as a constant light source aimed at the LDR. Smoke blocks this light to trigger the alarm.

2. LDR (Light Dependent Resistor):
   Detects light intensity. When smoke blocks the light, the LDR’s resistance increases, triggering a response in the circuit.

3. VR1 (100k Preset):
   Adjusts the sensitivity of the smoke detection by controlling the voltage divider with the LDR.

4. BC148 Transistor (NPN):
   Acts as a switch. It conducts when enough light falls on the LDR and turns off when smoke increases LDR resistance.

5. COB (Chip on Board):
   Likely a tone generator or logic module. Gets powered via the transistor and triggers output when smoke is detected.

6. VR2 (100k Preset):
   Controls the signal level or volume sent to the amplifier.

7. IC2 – TDA2002 Audio Amplifier:
   Amplifies the signal from the COB and drives the connected 8Ω speaker to sound an alert.

8. Speaker (8Ω):
   Outputs a loud alarm sound when smoke is detected.

9. Capacitors (C1: 470µF, C2: 1000µF):
   Provide filtering and stability to the amplifier circuit.

10. Resistors (R3: 220Ω, R4: 2.2Ω):
    Set gain and feedback for the amplifier.

11. Power Supply (9V Battery or Adapter):
    Provides operating voltage to the entire system.

Key Features:

• Optical Smoke Detection using bulb and LDR

• Transistor-controlled logic (BC148)

• Real-time fire alert using buzzer/speaker

• Adjustable sensitivity via VR1

• Audio amplification using TDA2002 for louder alarm

• Compact and cost-effective for academic or demo use

• Quick response time on detecting smoke

• Visual light-based detection instead of chemical/gas sensors

Applications:

• Fire detection in small project demonstrations

• Academic electronics projects and exhibitions

• Prototype for optical smoke detection systems

• Educational tool for learning sensor-based automation

• Early fire detection system in small-scale workshops (demo only)

To Learn More Visit our Website

For more information:-www.mifraelectronics.com 
* Product Images are shown for illustrative purposes only and may differ from actual product.