Generic Flame Sensor Module - LM393 Comparator, 760-1100nm IR, Digital/Analog Output

The module is designed to operate from 3.3 volts to 5.0 volts DC. This range makes it directly compatible with most 5V Arduino boards as well as 3.3V logic systems like the Raspberry Pi or ESP32, without requiring a level shifter.

The module provides two distinct outputs. The digital (D0) pin outputs a TTL-level signal, which goes LOW when a flame is detected above the set threshold. The analog (A0) pin outputs a variable voltage proportional to the infrared intensity, allowing for more nuanced flame presence or distance estimation in your code.

Sensitivity is adjusted via the blue potentiometer on the module. Turning it clockwise typically increases sensitivity, allowing detection of smaller or more distant flames. Calibrate it by observing the digital output LED or monitoring the analog value with a known flame source at your desired maximum range.

It is specifically sensitive to the infrared spectrum between 760nm and 1100nm, which is prominent in flame emissions. While it may trigger from other intense IR sources (like certain incandescent bulbs or sunlight), its black epoxy IR-filtered phototransistor (YG1006) is optimized to reduce response to visible light, improving flame specificity.

The LM393 is a precision voltage comparator. It compares the analog signal from the YG1006 sensor against a reference voltage set by the sensitivity potentiometer. This provides a clean, debounced digital output signal, eliminating the need for software thresholding and ensuring a stable, immediate trigger for alarms or robotic responses.