MQ2 Flammable Gas and Smoke Sensor Module

The MQ2 sensor element at the heart of this module changes its electrical resistance when it comes into contact with combustible gases and smoke particles, and the breakout board converts that into both an analog signal that scales with concentration and a digital trigger once a threshold is crossed. It responds to a useful range of household and workshop hazards, including LPG, butane, propane, methane, and general smoke, which makes it a common choice for DIY kitchen gas-leak alarms, smoking-detection projects, and workshop safety monitors that alert before a dangerous concentration builds up. Like other MQ-series sensors it needs a brief warm-up period after power-on before readings stabilize, a detail worth accounting for in firmware so a project doesn't react to a false high reading in its first few seconds of operation.