Indoor air quality monitor

The utility model relates to a device for detecting indoor oxygen content, belonging to air measuring device. The air quality monitor mainly comprises a casing, a sensing device (U ) and a control device. The casing is provided with a display screen, a keyboard and a warning lamp. The sensing device (U ) is a carbon dioxide sensing device which is connected with the control device. A control circuit comprises an operational amplifier (U ), an A/D converter (U ), a singlechip (U ), an alarm (U ), and a display modular (U ), wherein the singlechip (U ) controls every part of the circuit to operate. The device of the utility model has the advantages of low cost, high measurement accuracy, simple and reliable structure, convenient utilization and long service life.