This four-in-one gas detection module is primarily designed for various environments requiring ambient gas detection. The product includes four gas sensors (expandable to CO, H2S, O2, and CH4) and a signal processing circuit board. The module offers excellent selectivity and stability, and outputs real-time concentration values for the four gases via a digital serial port. It can be used in handheld or stationary devices to detect current ambient gas concentrations. This module is a versatile, miniaturized product that tightly integrates mature sensor detection technology with sophisticated circuit design.