Flame Sensor Interfacing with Arduino Uno

In this we are going to interface Flame Sensor with Arduino Uno and detect flames.

Components Required

Flame Sensor

Flame Sensor | Alpha Electronz
Flame Sensor

These types of sensors are used for short range fire detection and can be used to monitor projects or as a safety precaution to cut devices off / on. This Flame Sensor module is accurate up to about 3 feet. The flame sensor is very sensitive to IR wavelength at 760 nm ~ 1100 nm light.

Analog output (A0): Real-time output voltage signal on the thermal resistance.

Digital output (D0): When the temperature reaches a certain threshold, the output high and low signal threshold adjustable via potentiometer.


VCC – Positive voltage input: 5v for analog 3.3v for Digital.

A0 – Analog output

D0 – Digital output

GND – Ground

Circuit Diagram

Arduino Flame Sensor Circuit Diagram | Alpha Electronz
Arduino Flame Sensor Circuit Diagram

To connect the Flame Sensor to the Arduino connect the following as shown in the above Diagram:

Flame sensor – Arduino

VCC —> 5v


A0 —>  Analog in 0


// lowest and highest sensor readings:
const int sensorMin = 0; // sensor minimum
const int sensorMax = 1024; // sensor maximum

void setup() 
// initialize serial communication @ 9600 baud:

void loop() 
// read the sensor on analog A0:
int sensorReading = analogRead(A0);
// map the sensor range (four options):
// ex: 'long int map(long int, long int, long int, long int, long int)'
int range = map(sensorReading, sensorMin, sensorMax, 0, 3);
// range value:
switch (range) 
case 0: // A fire closer than 1.5 feet away.
Serial.println("** Close Fire **");
case 1: // A fire between 1-3 feet away.
Serial.println("** Distant Fire **");
case 2: // No fire detected.
Serial.println("No Fire");
delay(1); // delay between reads



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