This guide shows how to build a smoke detector that beeps when it detects flammable gas or smoke.
The MQ-2 Gas Sensor
The MQ-2 smoke sensor is the one in the following figure:
The MQ-2 smoke sensor is sensitive to smoke and to the following flammable gases:
The resistance of the sensor is different depending on the type of the gas.
The smoke sensor has a built-in potentiometer that allows you to adjust the sensor sensitivity according to how accurate you want to detect gas.
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