When the water level in the soymilk machine drops to the preset low level, the water level is lower than the fixed position of the non-contact liquid level sensor. This signal change will be interpreted by the sensor as the water level is too low, triggering the alarm of the soymilk machine or the automatic water adding device. Non-contact liquid level sensors The advantage of liquid level sensors is that they are independent of other properties, such as temperature, pressure, density, or electrical parameters, of the medium, and therefore can operate stably and reliably. It has the characteristics of low power consumption, high accuracy, convenient installation, stable chemical properties, and little impact on the measured medium. The sensor interior is specially treated, all the components are resin pouring seal, there is no mechanical moving parts, so it has the characteristics of long life and high reliability. The water level sensor of the soybean milk machine realizes the accurate detection and control of the water level through the photoelectric effect, so as to ensure that the water level of the soybean milk machine is always within the safe and appropriate range during the working process. Its advanced technology design and stable work performance, enable it to be widely used in the home and commercial places, to provide users with convenient and reliable use experience.