Description

The HW-491 Flame Sensor Module is an optical safety sensor built to identify naked fire flames or heat ignition sources in real time. Since open flames radiate strong infrared light, the module’s black-encapsulated photodiode focuses specifically on the near-infrared spectrum (760nm–1100nm) while filtering out common visible ambient light.

The board integrates an LM393 voltage comparator circuit alongside a high-precision multi-turn potentiometer. The Digital Output (DO) pin triggers a LOW/HIGH logic threshold directly to microcontrollers (Arduino, ESP32, Raspberry Pi) when a flame is detected, while the Analog Output (AO) pin provides raw voltage readings to determine flame distance or intensity.

Technical Specifications

Pinout Configuration

The module features a standard 4-pin male header layout:

Basic Arduino Wiring & Example Code

Wiring Diagram

• VCC (+) ➔ Arduino 5V (or 3.3V)

• GND (G) ➔ Arduino GND

• DO (D0) ➔ Arduino Digital Pin 2

• AO (A0) ➔ Arduino Analog Pin A0

// HW-491 Flame Sensor Basic Interfacing
const int flameDigitalPin = 2; // DO Pin connected to Digital Pin 2
const int flameAnalogPin  = A0;// AO Pin connected to Analog Pin A0

void setup() {
  pinMode(flameDigitalPin, INPUT);
  Serial.begin(9600);
  Serial.println("HW-491 Flame Sensor Initialized.");
}

void loop() {
  int digitalValue = digitalRead(flameDigitalPin);
  int analogValue  = analogRead(flameAnalogPin);

  Serial.print("Analog Level: ");
  Serial.print(analogValue);
  
  if (digitalValue == LOW) { // Onboard LM393 pulls DO LOW upon flame threshold
    Serial.println("  | WARNING: FLAME DETECTED!");
  } else {
    Serial.println("  | Status: Normal (No Flame)");
  }
  
  delay(300);
}

Key Features & Highlights

• Dual Signal Outputs: Supports both threshold digital switching (for immediate alarms/interrupts) and continuous analog intensity monitoring.

• Adjustable Sensitivity: Built-in trimmer potentiometer allows exact tuning to filter out ambient lighting and adjust detection range.

• Wide Voltage Range: Fully compatible with 3.3V microcontrollers (ESP32, STM32, Pi Pico) and 5V logic platforms (Arduino Uno, Mega).

• Fast Response Time: High-speed photodiode optical response ensures rapid emergency shutdown triggering during accidental flare-ups.

Common Applications

• Autonomous fire-fighting robots and automatic extinguisher platforms.

• Industrial boiler, gas stove, and burner ignition flame monitoring.

• Fire alarm systems, thermal runaway safety cut-offs, and emergency indicators.

• Educational STEM projects, safety automation labs, and DIY fire detectors.

What’s Included in the Box

• 1 × HW-491 Flame Sensor Infrared Receiver Module

Why Buy From Aryabot?

• 100% Quality Hardware: Built with stable LM393 ICs, high-grade photodiodes, and clean FR-4 glass-fiber PCB fabrication.

• Tested & Benchmarked: Pre-tested for optical response time, potentiometer threshold adjustments, and logic pin continuity.

• GST Invoice Provided: Tax-compliant B2B invoices generated for commercial deployments, educational institutions, and research labs.

• Pan-India Express Dispatch: Fast order processing and reliable direct delivery from our Noida fulfillment warehouse.