YF-S401C Hall Effect Water Flow Sensor 0.3-6L/min 1/8 Inch

The YF-S401C is a compact Hall effect water flow sensor designed to measure the rate of liquid flowing through a pipe or hose. It consists of a plastic valve body, a magnetic rotor, and a Hall effect sensor that is sealed from the water path, keeping the electronics safe and dry. When liquid flows through the sensor, the rotor spins at a rate proportional to the flow, and the Hall effect sensor outputs a square-wave pulse signal for each revolution. By counting these pulses with a microcontroller such as an Arduino, users can calculate the flow rate and total volume of liquid passing through the sensor.

This flow sensor features a 1/8-inch (approximately 3.5mm inner diameter) nozzle and supports a flow range of 0.3 to 6 liters per minute. The output pulse frequency follows the relationship F = (98 × Q) ± 2%, where Q is the flow rate in liters per minute, and each liter of water corresponds to approximately 5880 pulses (about 2.25 milliliters per pulse). The sensor operates on a supply voltage of 5V to 18V DC with a working current of 15mA, and it is compatible with both 5V and 3.3V logic microcontrollers. The output pulse high level exceeds 4.5V DC when powered from 5V, ensuring reliable signal detection.

The YF-S401C is suitable for a wide range of applications, including coffee machines, water dispensers, sprinkler systems, industrial gas and liquid measurement, compressed air monitoring, and general-purpose flow measurement in embedded projects. The sensor is designed for vertical installation with a tilt of no more than 5 degrees and should be used with a 6mm hose. It withstands water pressure up to 0.8MPa and liquid temperatures up to 120°C, making it a durable and versatile choice for both hobbyist and commercial flow-sensing applications.