The YF-S201 is a hall effect-based water flow sensor that measures the amount of liquid flowing through your water line. It features an integrated magnetic hall effect sensor that generates an electrical pulse each time the pinwheel spins. The sensor is designed with safety in mind, as it is sealed from the water pipe and the hall effect sensor remains dry.

The sensor is easy to use, with three simple connections: red (5-24VDC power), black (ground), and yellow (Hall effect pulse output). The pulses from the sensor can be counted to determine the water flow, with each pulse representing approximately 2.25 millilitres. While the sensor is not particularly precise, it is ideal for basic measurement tasks.

The sensor comes with an Arduino sketch that can be used to test its functionality, which will calculate the approximate water flow in litres per hour. The pulse signal is a straightforward square wave that can easily be logged and converted into litres per minute using the formula: Pulse frequency (Hz) / 7.5 = flow rate in L/min.

Features:

Model: YF-S201
Sensor Type: Hall effect
Working Voltage: 5 to 18V DC (min tested working voltage 4.5V)
Maximum Current Draw: 15mA @ 5V
Output Type: 5V TTL
Working Flow Rate: 1 to 30 Litres/Minute
Operating Temperature Range: -25 to +80℃
Operating Humidity Range: 35%-80% RH
Accuracy: ±10%
Maximum Water Pressure: 2.0 MPa
Output Duty Cycle: 50% +-10%
Output Rise Time: 0.04us
Output Fall Time: 0.18us
Flow Rate Pulse Characteristics: Frequency (Hz) = 7.5 * Flow rate (L/min)
Pulses per Litre: 450
Durability: minimum 300,000 cycles
Cable Length: 15cm
Nominal Pipe Connections: 1/2″, Outer Diameter: 0.78″, Thread Length: 1/2″
Size: 2.5″ x 1.4″ x 1.4″