Description

Principle of Working

The circuit shown can be used as a small automatic fire-extinguishing prototype. For an actual fire-extinguisher system, a proper flame sensor should be used rather than a simple obstacle/proximity sensor.

Apparatus Required

1. Flame sensor – 1
2. 5 V/9 V relay module – 1
3. DC water pump – 1
4. 9 V battery – 1 or 2, depending on the voltage/current requirements of the pump
5. Battery connectors – 1–2
6. Connecting wires
7. Plastic pipe/tube
8. On/Off switch – optional

Principle of Working

The automatic fire extinguisher works on the principle of flame detection using infrared radiation.

A flame produces infrared radiation. The flame sensor detects the IR radiation from the flame and produces an electrical output signal. This signal activates the relay, which acts as an automatic switch.

The relay then supplies power to the DC water pump. The pump draws water from the tank and sends it through the pipe to the spray nozzle, thereby extinguishing the fire.

Simple Block Diagram

Flame → Flame Sensor → Relay → Water Pump → Nozzle → Water Spray

Working

1. Normal condition:
   The flame sensor continuously monitors the surrounding area. The pump remains OFF.
2. Fire detection:
   When a flame appears within the sensor’s detection range, the sensor detects the infrared radiation from the flame.
3. Relay activation:
   The sensor output activates the relay.
4. Pump starts:
   The relay connects the battery supply to the DC water pump.
5. Water spraying:
   The pump draws water from the tank and sends it through the pipe and nozzle toward the fire.
6. Fire extinguishing:
   The water spray reduces the temperature of the burning material and helps extinguish the flame.
7. Automatic stopping:
   When the flame is no longer detected, the sensor output changes and the relay switches the pump OFF.

Important correction to your shown circuit

The sensor in your uploaded diagram appears to be an IR obstacle/proximity sensor, which detects reflected objects. For an automatic fire extinguisher, replace it with a flame sensor module designed to detect flame/IR radiation.

Also, a small 9 V rectangular battery may not provide enough current for many DC pumps. Check the pump’s rated voltage and current before connecting it. For a school-project prototype, a low-voltage DC pump and a suitable power supply are preferable.

Safety: This is suitable as an educational prototype. Do not rely on it as the sole protection against a real fire; use certified fire-safety equipment for actual fire protection.