This MicroPython code reads the infrared analogue signal from an IR module (ignoring the DI signal), and outputs the converted analogue value read, as well as generating its own digital signal (“FLAME DETECTED! 🔥”) based on the captured threshold value (FLAME_THRESHOLD).
The sample program is written for the LM393 (KY-026) Flame Sensor Module.
import machine import time # Configure ADC0 on GPIO26 flame_sensor = machine.ADC(26) # Calibration threshold (0-65535) # Most analog flame sensors output a LOWER voltage when a flame is detected. # Adjust this value based on your ambient light conditions. FLAME_THRESHOLD = 50000 print("Starting Flame Sensor Monitoring...") while True: # Read the 16-bit analog value (range: 0 to 65535) raw_value = flame_sensor.read_u16() # Calculate the corresponding voltage (based on 3.3V reference) voltage = (raw_value * 3.3) / 65535 # Evaluate the sensor readings # Typical flame sensors pull the analog output LOW in the presence of fire. if raw_value < FLAME_THRESHOLD: status = "FLAME DETECTED! 🔥" else: status = "Safe / No Flame" # Print results to the serial console print(f"ADC Value: {raw_value:5d} | Voltage: {voltage:.2f}V | Status: {status}") # Wait 200 milliseconds before the next sample time.sleep(1)
Output example
ADC Value: 62495 | Voltage: 3.15V | Status: Safe / No Flame ADC Value: 2880 | Voltage: 0.15V | Status: FLAME DETECTED! 🔥 ADC Value: 63231 | Voltage: 3.18V | Status: Safe / No Flame ADC Value: 62815 | Voltage: 3.16V | Status: Safe / No Flame ADC Value: 2624 | Voltage: 0.13V | Status: FLAME DETECTED! 🔥 ADC Value: 2528 | Voltage: 0.13V | Status: FLAME DETECTED! 🔥 ADC Value: 2912 | Voltage: 0.15V | Status: FLAME DETECTED! 🔥 ADC Value: 3760 | Voltage: 0.19V | Status: FLAME DETECTED! 🔥 ADC Value: 63247 | Voltage: 3.18V | Status: Safe / No Flame ADC Value: 63279 | Voltage: 3.19V | Status: Safe / No Flame
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