Water Flow Sensor - YF-S201B

Key Features

• Measures water flow accurately using a Hall-effect sensor.
• Simple 3-wire connection (VCC, GND, Signal).
• Compatible with most microcontrollers like Arduino, Raspberry Pi, and ESP boards.
• Durable plastic body with high corrosion resistance.

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Specifications

• Model: YF-S201B
• Operating Voltage: 5V–18V DC
• Output Signal: Pulse signal (Hall effect sensor)
• Flow Rate Range: 1–30 liters per minute (L/min)
• Pulse Frequency: 4.5 pulses per liter (approx., varies by water pressure and pipe conditions)
• Accuracy: ±10%
• Maximum Pressure: ≤ 1.75 MPa
• Pipe Diameter: G1/2 (1/2 inch)
• Working Temperature: -20°C to 80°C
• Material: Food-grade plastic

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Working Principle

• The sensor has a rotor with blades inside the water passage.
• As water flows, the rotor spins, and a Hall-effect sensor detects the magnetic pulses generated by the spinning rotor.
• The output is a pulse signal, where the frequency corresponds to the flow rate.

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Pinout

1. Red Wire: Power (VCC)
2. Black Wire: Ground (GND)
3. Yellow Wire: Pulse Signal (Connect to a GPIO pin)

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Formula to Calculate Flow Rate

The pulse frequency output by the sensor can be used to calculate the flow rate using the formula:

Q=PulseFrequencyK×TQ = frac{PulseFrequency}{K times T}Q=K×TPulseFrequency​

Where:

• Q: Flow rate in liters per minute (L/min)
• PulseFrequency: Measured pulses per second
• K: Calibration factor (usually 4.5 pulses per liter, check the datasheet)
• T: Time interval (seconds) over which pulses are measured

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Interfacing with Arduino

Hardware Setup

1. Connect the red wire to the Arduino's 5V pin.
2. Connect the black wire to GND.
3. Connect the yellow wire to a digital pin, e.g., D2.

Applications

• Water dispensers
• Home automation (water usage monitoring)
• Agricultural irrigation systems
• Industrial fluid measurement
• Cooling systems