Arduino Flow meter


YF-S201 Hall Effect Water Flow Sensor

This YF-S201 Water Flow Sensor is designed with a 1/2” plastic pipe that incorporates a wheel. The wheel rotates with the flow of water. A Hall Effect Sensor is integrated with the wheel. When the wheel revolves, the Hall Effect Sensor generates an electrical pulse. The number of electrical pulses varies with the flow of water. Each pulse stands for approximately 2.25 milliliters of water. The number of pulses is determined using a microcontroller. 

YF-S201 Hall Effect Water Flow Sensor

Specs of YF-S201 Hall Effect Water Flow Sensor:

  • 1 to 30 Liters/Minute flow rate measurement
  • Liter(s) per minute = Number of Pulses / 7.5
  • 10% tolerance
  • 4.5-18V DC input voltage
  • 5V TTL Signal
  • -25°C to +80°C temperature range
  • 35% to 80% humidity range
  • 50% to -10% output duty cycle range
  • 2.0MPa maximum water pressure
  • 0.04us output rise time
  • 0.18us output fall time
  • 450 pulses per liter of flow
  • 1/2” pipe connection
  • 2.5” x 1.4” x 1.4” dimensions


Wiring the Flow Sensor with Arduino:

YF-S201 Hall Effect Water Flow Sensor Wiring

Connect all pins as following

  • Red Wire with +5V pin of Arduino Board
  • Black Wire with the GND (ground) pin of Arduino
  • Yellow Wire with a Digital pin of Arduino (preferably pin 2)


Package Contains:



YF-S201 Hall Effect Water Flow Sensor Application

This Water Flow Sensor can be used in automation applications where liquid flow rate measurement is needed e.g it can be used for monitoring and controlling the rate of water flowing in the water tank, water dispenser, and coffee machine. It can also be used for the development of automated plants watering system.



1. What is the maximum flow range of this sensor?

YF-S201 supports up to 30 Liters of water per minute.


    2. What is the tolerance level of this sensor?

YF-S201 has 10% tolerance.


    3. Is this sensor easy to use for hobby projects?

Yes, YF-S201 is easy to use and its compatibility makes it easy to sync with common microcontrollers such as Arduino Boards.


4. What is the life expectancy of this sensor?

YF-S201 operates for more than 300,000 cycles


    5. Is this sensor suitable for high-temperature applications?

YF-S201 sensor operates below +80°C temperature.

6. How do I connect YF-S201 Flow Sensor with Arduino Board?

We have a detailed tutorial which shows how to connect this sensor and read the data, it can be found here:






Price: $39.99
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