IR Flame Sensor Module - 3-Pin Digital Fire Detector with LM393 Comparator

Specifications

• Operating Voltage: 3.3V to 5V DC

• Detection Range: 760nm to 1100nm (Infrared)

• Detection Angle: Approximately 60 degrees

• Detection Distance: ~80cm (for a standard lighter flame)

• Output Type: Digital (DO) - High/Low

• Comparator Chip: LM393

• Sensitivity: Adjustable via onboard blue potentiometer

Key Applications and Projects

• Autonomous Firefighting Robots: Mounting three of these sensors in a fan shape on the front of a robot chassis, allowing the robot to accurately track and steer toward a flame to extinguish it with a mini water pump.

• Instant Fire Alarms: Pairing this sensor with an active buzzer to create a rapid-response fire alarm for a workshop laser cutter enclosure.

• Smart Home Safety: Wiring the sensor to an ESP8266 or ESP32 to send an emergency push notification to your phone if a fire breaks out in the kitchen.

Unlock New Capabilities (Project Evolution)

• The Ultimate Environmental Monitor: A flame sensor is excellent, but it cannot "see" through walls or around corners. Evolve your safety system! Combine this IR flame sensor with an MQ-2 Gas/Smoke Sensor. While the IR sensor will instantly catch a flash fire in its direct line of sight, the MQ-2 will detect the thick, smoldering smoke of a hidden electrical fire before it even produces a flame. Combining both gives your Arduino project a foolproof, commercial-grade safety net!

Package Includes:

• 1 x IR Fire Detector Sensor Module (3-Pin Digital)

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What exactly does this sensor do? It detects the presence of an open flame or fire by sensing the specific infrared (IR) light wavelengths that fires emit.

2. Can it detect smoke or dangerous gases? No. This is purely an optical (light-based) sensor. It cannot smell smoke or gas. You would need an MQ-series sensor for that.

3. What is the black, bulbous component on the front? That is the IR photodiode receiver. It is the actual component that "sees" the infrared light.

4. Why is the photodiode black instead of clear like a normal LED? The black epoxy is a specialized daylight filter. It blocks out standard visible light from lightbulbs so the sensor isn't constantly giving false alarms, allowing only infrared light to pass through.

5. How far away can it detect a fire? It depends heavily on the size of the fire. It can detect a small cigarette lighter flame from about 80cm (roughly 2.5 feet) away. A larger fire can be detected from much further away.

6. What is the blue box with the cross-slot on top? That is a potentiometer (a variable resistor). You turn it with a small screwdriver to adjust the sensitivity (how large or close a fire needs to be to trigger the sensor).

7. What do the three pins do? VCC is for positive power, GND is for ground, and DO is the Digital Output signal that goes to your microcontroller.

8. Does this output an analog signal? No. This specific 3-pin version only outputs a Digital (DO) High/Low signal. It tells the Arduino "Yes, there is a fire" or "No, there is not a fire."

9. What does the LM393 chip do? The LM393 is a voltage comparator. It compares the raw analog voltage from the photodiode to the voltage set by your blue potentiometer. When the photodiode voltage crosses that threshold, the chip snaps the digital output pin cleanly on or off.

10. What voltage does this board require? It operates safely on anything between 3.3V and 5V DC.

11. Can I use this with a 3.3V Raspberry Pi or ESP32? Yes! Because it supports 3.3V power, the digital output will also be a safe 3.3V logic level, meaning it won't damage your Raspberry Pi or ESP32 pins.

12. Do I need a special library to use this with Arduino? No special library is required. You simply use the standard pinMode(pin, INPUT) and digitalRead(pin) commands.

13. Will sunlight set off a false alarm? Yes, it is very possible. The sun is a massive source of infrared radiation. If direct, intense sunlight hits the black sensor, it may trigger a false positive. This sensor is best utilized indoors or in shaded environments.

14. What are the two tiny LEDs on the board for? One is a "PWR-LED" that stays on as long as the board has power. The other is a "DO-LED" that lights up immediately when the sensor detects a flame.

15. How do I calibrate it without coding? Power the board with 5V and GND. Hold a lighter in front of it at your desired detection distance. Turn the blue potentiometer screw until the DO-LED just barely lights up. The sensor is now calibrated to that distance!

16. Is this sensor waterproof? No, the exposed PCB and components will short out if exposed to water.

17. Can I place the sensor directly inside or very close to a fire? NO. The sensor detects the light of the fire, not the heat. If you put it too close to an actual flame, the plastic photodiode and the circuit board will quickly melt and be destroyed.

18. What is the "viewing angle" of the sensor? The black photodiode has a viewing angle of approximately 60 degrees. It acts like a cone projecting forward. It will not easily detect a fire directly behind it.

19. How can a robot find the direction of a fire if the angle is only 60 degrees? Robot builders typically mount 3 to 5 of these sensors in a curved array (left, center, right). By checking which specific sensor is triggered, the robot knows which way to turn.

20. Why are there extra solder pads near the photodiode on some boards? Some generic board blanks are designed to accommodate different types of sensors. The circuitry is perfectly fine as built from the factory.