1) What the KY-026 does (and does not do)

The KY-026 module detects the presence of a flame by sensing infrared radiation typically emitted by burning materials (around 760–1100 nm).

Good use cases

• Flame presence detection
• Fire alarm triggers (with validation)
• Educational demonstrations
• Robotics flame-finding projects

Not suitable for

• Precise temperature measurement
• Smoke detection (use smoke sensors instead)
• Outdoor detection without shielding and filtering

2) How infrared flame detection works

Flames emit strong infrared radiation due to excited molecules and hot particles. The KY-026’s IR photodiode converts this radiation into a small electrical signal.

• Stronger flame ? stronger IR signal
• Distance and angle strongly affect response
• Flickering flames produce fluctuating signals

3) Module overview and internal circuitry

The KY-026 typically includes:

• Infrared photodiode or phototransistor
• LM393 comparator
• Potentiometer for threshold adjustment
• Status LED (digital output indicator)

The analog signal feeds the comparator, which produces a digital HIGH/LOW output depending on the set threshold.

4) Pinout and electrical characteristics

• Compatible with 3.3V and 5V microcontrollers
• Digital output is TTL-level

5) Analog vs digital output behavior

Analog Output (AO)

• Represents raw IR intensity
• Higher value ? stronger IR detected
• Used for calibration and advanced logic

Digital Output (DO)

• Comparator-based ON/OFF signal
• Threshold adjustable via potentiometer
• Often active LOW when flame is detected (verify)

6) Sensitivity and threshold adjustment

1. Power the module and connect DO to a digital input.
2. Open Serial Monitor to observe DO state.
3. Introduce a flame at the desired detection distance.
4. Turn the potentiometer slowly until DO switches reliably.
5. Verify stability by removing and reintroducing the flame.

7) Wiring to Arduino

KY-026 VCC ? Arduino 5V (or 3.3V)
KY-026 GND ? Arduino GND
KY-026 AO  ? Arduino A0
KY-026 DO  ? Arduino D2
    

8) Arduino Example 1: Analog flame intensity

/*
  KY-026 Flame Sensor - Analog Read
  Product #215
*/

const int FLAME_AO = A0;

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

void loop() {
  int value = analogRead(FLAME_AO); // 0–1023
  Serial.print("IR Intensity: ");
  Serial.println(value);
  delay(200);
}
    

9) Arduino Example 2: Digital flame detection

/*
  KY-026 Flame Sensor - Digital Detection
*/

const int FLAME_DO = 2;

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

void loop() {
  if (digitalRead(FLAME_DO) == LOW) {
    Serial.println("Flame detected");
  } else {
    Serial.println("No flame");
  }
  delay(200);
}
    

10) Arduino Example 3: Flame alarm logic

/*
  Simple Flame Alarm Logic
*/

const int FLAME_DO = 2;
const int BUZZER  = 8;

void setup() {
  pinMode(FLAME_DO, INPUT);
  pinMode(BUZZER, OUTPUT);
}

void loop() {
  bool flame = (digitalRead(FLAME_DO) == LOW);

  if (flame) {
    digitalWrite(BUZZER, HIGH);
  } else {
    digitalWrite(BUZZER, LOW);
  }
}
    

11) Detection angle and distance

• Typical detection range: up to ~50–80 cm for small flames
• Detection angle: roughly 60° (module-dependent)
• Best detection when flame is centered in field of view

12) Sunlight and false triggers

• Sunlight contains strong IR ? shield sensor if possible
• Incandescent bulbs emit IR ? may trigger detection
• Use flicker detection or multiple samples for validation
• Combine with temperature or smoke sensors for safety systems

13) Typical applications

• Fire detection alarms
• Flame-following robots
• Industrial safety monitoring
• Educational sensor experiments

14) Troubleshooting

Always triggered

• Sensitivity set too high
• Direct sunlight or IR source nearby
• Incorrect wiring

Never triggered

• Sensitivity too low
• Flame too far or off-axis
• Wrong assumption about DO polarity

15) Quick checklist

KY-026 Flame Detection Module (#215) Checklist
---------------------------------------------
? Power with 3.3V–5V
? Use AO for calibration and advanced logic
? Use DO for simple flame detection
? Adjust potentiometer under real conditions
? Expect IR-based false triggers; validate in software
? Shield from sunlight when possible
? Combine with other sensors for safety-critical systems