Smoke calculation with mq2 sensor
This is an SnO2 combustible gas (and CO) sensor, not a smoke sensor.
Refer to the (typical) &quot;Sensitivity Characteristics&quot; curve in the sensor datasheet. Ask your supplier for a link to the datasheet if you can't find it.
The typical sensor resistance is given relative to the resistance in a calibration gas such as 1000ppm hydrogen or 1800ppm iso-butane. If you can't immerse each sensor individually in the calibration gas to calibrate it, it's fairly pointless. There is also substantial variation with temperature and humidity.
The unit-to-unit variation in absolute resistance terms under calibration conditions can be about an order of magnitude.