Initialization: The Arduino initializes the pins for the flame sensor, built-in LED, and external LED, and begins serial communication. Flame Detection: The flame sensor reads the presence of a flame ...

The left flame sensor is connected to pin 2, the right flame sensor is connected to pin 3, center flame sensor is connected to pin4. The center flame sensor if using has 4 pins àvcc, gnd, d0, a0 then ...