Sensor is a detection device, can feel the measured information, transform information into electrical signals or other information in the form of output required to meet the information transmission, processing, storage, display, record and control requirements.
The characteristics of sensor include: miniaturization, digitalization, intelligentization, multi-function, systematization and networking. It is the primary part to realize automatic detection and automatic control. The existence and development of the sensor let the object have sense of touch, taste and smell, and let the object become more and more smart. Usually, according to its basic sensing function, it can be divided into ten main categories: heat sensitive element, photosensitive element, gas sensitive element, force sensitive element, magnetic sensor, humidity sensor, acoustic sensor, radiation sensitive element, color sensitive element and odor sensor.