An electronic nose is a technical system for odor measurement and digitization of the sense of smell. This makes it possible to develop cost-effective and practical olfactory systems that can be used in industry, food analysis, quality monitoring, environmental protection, and, especially, in medicine. With the help of microelectronic sensors, the eNose detects gaseous compounds in the air and converts them into a specific electrical pattern, depending on the signal strength of the individual sensors. The CO2 detector, the exhaust gas detector in cars, is actually a simple example of an eNose.