IR Flame Sensors - Elegets Learn

IR Flame Detection Overview

IR flame sensors detect fire or other light sources in the infrared spectrum, typically between 760nm to 1100nm wavelength, which is the range where most flames emit significant radiation.

IR Sensitivity: Detects specific IR wavelengths emitted by flames
Fast Response: Typically responds within milliseconds
Adjustable Sensitivity: Most modules have potentiometer for threshold adjustment
Digital/Analog Output: Provides both digital (on/off) and analog (intensity) outputs
Wide Detection Angle: Typically 60° field of view

Non-Contact Detection: Can detect flames from a distance
Works in Darkness: Doesn't require visible light
Low Cost: Affordable fire detection solution
Easy to Interface: Simple digital/analog outputs
Reliable: Less prone to false alarms than smoke detectors

Fire Alarm Systems: Early fire detection
Industrial Safety: Monitoring furnaces and boilers
Robotics: Fire-fighting robots
Smart Home: Stove/oven monitoring
Automotive: Engine compartment monitoring

Flame Sensor Types

Standard IR Flame Sensor

Detects 760nm-1100nm IR radiation
3-pin interface (VCC, GND, OUT)
Adjustable sensitivity via potentiometer
Digital (HIGH/LOW) output
Detection range: 0.8m-1.5m

Common Low Cost

5-Channel IR Flame Sensor

5 separate IR receivers at different angles
Can determine flame direction
Analog outputs for each channel
Better false alarm rejection
Detection range: up to 3m

Directional Advanced

UV/IR Flame Sensor

Combines UV and IR detection
Higher reliability (fewer false positives)
Industrial-grade performance
Longer detection range (up to 10m)
More expensive

Industrial High Reliability

Comparison of Flame Sensor Types

Parameter	Standard IR	5-Channel IR	UV/IR Combo
Detection Range	0.8m-1.5m	Up to 3m	Up to 10m
Field of View	60°	5x 30° channels	90°
Response Time	100ms	50ms	30ms
False Alarm Rate	Medium	Low	Very Low
Price Range	$1-$5	$10-$20	$50-$200

How IR Flame Sensors Work

Working Principle

IR Detection: Specialized photodiode sensitive to IR wavelengths emitted by flames
Signal Amplification: Weak IR signal is amplified by operational amplifier
Threshold Comparison: Signal compared to adjustable threshold voltage
Output Trigger: Digital output goes LOW when flame detected
Analog Output: Provides raw signal level for intensity measurement

Flame Characteristics

IR Emission: Flames emit strongly in 760nm-1100nm range
Flicker Pattern: Most flames flicker at 1-10Hz
False Sources: Sunlight, incandescent bulbs, heaters
Detection Angle: Affected by sensor's field of view
Distance Factors: Intensity follows inverse square law

Typical Response Curve

Detection Optimization

Positioning: Mount sensor to cover risk areas
Sensitivity Adjustment: Set threshold to avoid false alarms
Flicker Analysis: Software can analyze flicker pattern
Multiple Sensors: Combine for better coverage
Environmental Factors: Account for ambient IR sources

Pinout and Wiring

Standard 4-Pin Module

VCC (3.3V-5V): Power supply
GND: Ground connection
DO (Digital Out): TTL output (LOW when flame detected)
AO (Analog Out): Analog voltage proportional to IR intensity

Module Components

IR Receiver: Specialized photodiode
LM393 Comparator: For digital output
Potentiometer: Adjusts detection threshold
Amplifier Circuit: Boosts weak IR signal
Status LED: Visual detection indicator

Typical Wiring Diagram

Important Wiring Notes

Power Requirements: Typically 3.3V-5V, low current (~15mA)
Analog Reference: Use clean power supply for accurate readings
Digital Output: Active LOW (goes LOW when flame detected)
Pull-Up Resistor: May need external pull-up for digital output
Sensor Placement: Avoid direct sunlight or strong IR sources

Flame Sensor Libraries

Popular Libraries

FlameSensor

Simple library for basic flame detection

Arduino Basic Digital

GitHub

AdvancedFlame

Advanced library with flicker analysis

Arduino Flicker Detection Analog

GitHub

MultiFlame

Library for multi-sensor arrays

Arduino 5-Channel Directional

GitHub

Basic Library Usage

// Basic Flame Sensor Example
#define FLAME_DIGITAL 2
#define FLAME_ANALOG A0

void setup() {
    Serial.begin(9600);
    pinMode(FLAME_DIGITAL, INPUT);
}

void loop() {
    int digitalVal = digitalRead(FLAME_DIGITAL);
    int analogVal = analogRead(FLAME_ANALOG);
    
    Serial.print("Digital: "); Serial.print(digitalVal);
    Serial.print(" | Analog: "); Serial.println(analogVal);
    
    if(digitalVal == LOW) {
        Serial.println("FLAME DETECTED!");
        // Trigger alarm or other actions
    }
    delay(200);
}

Advanced Flicker Detection

// Flame flicker detection example
#define FLAME_ANALOG A0
#define SAMPLE_SIZE 100
#define FLICKER_THRESHOLD 50

int samples[SAMPLE_SIZE];
int sampleIndex = 0;

void setup() {
    Serial.begin(9600);
}

void loop() {
    samples[sampleIndex] = analogRead(FLAME_ANALOG);
    sampleIndex = (sampleIndex + 1) % SAMPLE_SIZE;
    
    if(sampleIndex == 0) {
        int flickerCount = 0;
        for(int i = 1; i < SAMPLE_SIZE; i++) {
            if(abs(samples[i] - samples[i-1]) > FLICKER_THRESHOLD) {
                flickerCount++;
            }
        }
        
        if(flickerCount > SAMPLE_SIZE/4) {
            Serial.println("Flame flicker detected - real fire!");
        }
    }
    delay(10);
}

Project Ideas

Smart Fire Alarm

Combine flame sensor with buzzer, LED, and WiFi module for remote alerts.

Flame Sensor ESP8266 Blynk

Fire-Fighting Robot

Autonomous robot that detects and extinguishes small fires.

Flame Sensor Arduino Water Pump

Industrial Flame Monitor

Monitor furnace flames with multiple sensors and data logging.

5-Channel Sensor SD Card OLED

Campfire Safety Monitor

Portable device that monitors campfire safety and alerts if fire spreads.

Flame Sensor LiPo Battery Buzzer

Stove Safety System

Kitchen monitor that detects unattended stove flames and shuts off gas.

Flame Sensor Gas Valve ESP32

Flame Direction Tracker

Pan-tilt camera mount that automatically points toward detected flames.

5-Channel Sensor Servos Camera

Advanced Project: Autonomous Fire Detection Drone

// Components needed:
- Flame Sensor Array
- ESP32-CAM
- GPS Module
- Brushless Motors
- Flight Controller
- Telemetry Radio
- LiPo Battery

// Features:
1. Autonomous flight pattern
2. Real-time flame detection
3. GPS location tagging
4. Live video feed
5. Automatic return-to-home
6. Fire size estimation

// Implementation Tips:
- Use Pixhawk or similar flight controller
- Implement computer vision for flame verification
- Create heatmap of fire locations
- Integrate with emergency services API
- Implement failsafe mechanisms
- Optimize battery life for maximum flight time

Best Practices & Tips

Calibration

Adjust potentiometer for desired sensitivity
Test with actual flame at expected distance
Account for ambient IR sources
Set threshold to avoid false positives
Document settings for reproducibility

Installation

Mount at appropriate height (flame level)
Ensure clear line of sight to monitored area
Protect from dust and moisture
Avoid direct sunlight exposure
Consider multiple sensors for large areas

Signal Processing

Use moving average for stable readings
Implement flicker analysis for reliability
Set appropriate debounce time
Combine with other sensors (smoke, temp)
Log raw data for system improvement

Common Mistakes to Avoid

Mistake	Consequence	Solution
Improper sensitivity	False alarms or missed detections	Calibrate in actual operating environment
Poor placement	Reduced detection capability	Mount at flame height with clear view
Ignoring ambient IR	False positives	Account for sunlight, heaters, etc.
No signal processing	Unstable readings	Implement filtering and flicker analysis
Single point of failure	System vulnerability	Use multiple sensors in critical applications