Raspberry Pi Arduino Water Level Liquid Sensor Automatic Irrigation Aquarium Item dimensions L x W x H: 8.27 x 1.42 x 2.8 inches This photoelectric liquid level sensor operates on optical principles and features an open-collector output, making it compatible with a wide range of circuits and product applications. With no mechanical components and requiring no additional adjustment, it offers high sensitivity, low power consumption, corrosion resistance, high pressure tolerance, high temperature resistance, and chemical stability. The compact sensor probe can be installed in multiple orientations—upward, downward, sideways, or at an angle—to detect solution overflow, dryness, and horizontal liquid level, enabling it to serve in reminder and alarm functions. A built-in DIP switch allows control of the signal terminal (green wire) output voltage (high level). When set to 5V, the high level is 5V; when set to 3V, the high level is 3.3V. It is compatible with Arduino and Raspberry Pi motherboards and is well-suited for automatic irrigation systems, aquariums, plant care, gardening, agricultural applications, and more.