من کد رو به صورت زیر عوض میکنم
کد:

//You may copy, alter and reuse this code in any way you like but please leave reference to HobbyComponents.com in your comments if you redistribute this code.
//This code is modified by Ahlskog Niki & Borgström Anders

//SENSOR PINOUT:

#define FLAME_DETECT_ANA A0 // Select the input pin for the flame detectors analogue output.
#define FLAME_DETC_DIO 2 // Select the input pin for the flame detectors digital output.

int led = 8; // Select the input pin for the led

void setup() // Initialize serial and DIO
{

Serial.begin(9600); // Setup the serial port for displaying the status of the sensor
pinMode(led, OUTPUT);

pinMode(FLAME_DETC_DIO, INPUT); // Configure the DIO pin the sensors digital output will be connected to
}

void loop() // Main program loop
{

Serial.print("Sensor Value: "); // Read the sensors analogue output and send it to the serial port
Serial.print(analogRead(FLAME_DETECT_ANA));
delay(1000);
if (!digitalRead(FLAME_DETC_DIO)) // Read the status of the sensors digital output and if it is high then send an alert to the UART and the led is lighten
{
Serial.println(" FLAME DETECTED!");
digitalWrite(led, HIGH);
delay(1000);
digitalWrite(led, LOW);

}else // Otherwise the there is no alert and the led is shut down
{
Serial.println();
digitalWrite(led, LOW);
}
}
دلیلش اینه ماژول سایت فقط D0 داره و این کد برای A0 D0 نوع دیگری 4 پایه ماژول هست نه 3 پایه
در نتیجه همیشه flame detected میده
که من یه delay اضافه کردم و قسمت digitalRead(FLAME_DETC_DIO) رو not کردم

توضیحات تکمیلی
کد:

How it works:

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
.