A sensor is a detection device that can sense the measured information and transform the detected information into electrical signals or other required forms of information output according to certain rules, in order to meet the requirements of information transmission, processing, storage, display, recording, and control. It is the primary link to achieve automatic detection and control.

The narrow definition of a sensor is a device or device that can convert external non electrical information into electrical signals for output. The broad definition of a sensor: "Any device or device that utilizes certain material (physical, chemical, biological) laws, theorems, laws, effects, etc. for energy conversion and information conversion, and whose output and input strictly correspond to each other, can be called a sensor.

In the 21st century of informatization, sensors cannot be separated. The application fields of sensors are very extensive, including electronic computers, production automation, modern information, transportation, chemistry, environmental protection, energy, ocean development, remote sensing, aerospace, and so on. Sensors are also widely used in robots. At present, robots have gradually replaced human work in places with high labor intensity or hazardous operations. Some high-speed and high-precision tasks are also very suitable for robots to undertake. However, most of these robots are used for processing, assembly, inspection, and other work, and are mostly single energy robots of the automatic mechanical type used in production. Only sensors that detect the position and angle of the arm are used on these robots.

In order to make the robot and human function more similar, so as to engage in more demanding work and require the robot to be able to judge, it is necessary to equip the robot with object inspection sensors, especially visual sensors and Tactile sensor, so that the robot can recognize and detect objects through vision, and generate pressure, force, sliding and weight senses through touch. This type of robot is called an intelligent robot, which can not only perform special tasks, but also handle general production, affairs, and household chores, all of which can be handled by intelligent robots. This is currently one of the main research objects for the development of robots.