Pipeline capacitor liquid level sensors play a crucial role in modern intelligent devices, especially in applications that need to detect water shortage. Compared with traditional floating ball switches, this sensor has the advantages of high reliability, stability and not easy jamming. Its advanced capacitive induction principle requires mechanical motion, ensuring a long life and stable performance. Compared with the mechanical type, the pipe capacitor liquid level sensor has obvious advantages in accuracy and reliability, which solves the mechanical sensor is easy to jam failure. Therefore, it is widely used in a variety of smart home appliances. Sweeping robot is one of the main applications of pipeline liquid level sensor, which can accurately detect the water level in the water tank to ensure that there is enough moisture for the mopping function in the cleaning process. When the water level is too low, the sensor will issue an alarm or automatically stop the water supply to avoid poor cleaning effect or equipment damage caused by water shortage. In the water dispenser equipment, the liquid level sensor of the pipeline can accurately control the water level of the water tank inside the water dispenser, to avoid the low drinking water level affecting the drinking water quality or the overflow phenomenon due to the high water level. This high-precision detection ability not only ensures the normal operation of the water dispenser, but also improves the user experience.