Description MQ-9 is a semiconductor gas sensor designed to detect the presence of carbon monoxide (CO) and various combustible gases, including methane (CH₄), propane (C₃H₈), and liquefied petroleum gas (LPG). Its high sensitivity enables early detection of CO concentrations ranging from 10 to 1,000 parts per million (ppm) and combustible gases from 100 to 10,000 ppm. The sensor operates effectively within temperatures of -10°C to 50°C and requires a 5V power supply, consuming approximately 150 mA. It offers both analog and digital outputs, facilitating straightforward integration with microcontrollers like Arduino for applications such as gas leakage detection in domestic and industrial setting
