Liquid Flow Meter – YF-S201


Liquid Flow Meter – YF-S201


SKU: SEN-001 - Mfg Part Number: YF-S201


This type of flow sensor is used to measure liquid flow within a pipe and is ideally suited for monitoring water consumption in irrigation control systems. Each side of the sensor has a 1/2″ NPS nominal pipe connections, 0.78″ outer diameter, 1/2″ of thread. The sensor is connected by way of a 3 pin connector.

Inside the housing, a small pinwheel with an attached magnet is spun by passing water; as the magnet makes each revolution, a hall effect sensor inside the housing outputs a pulse on the yellow wire. Each pulse output represents approximately 2.25mL of fluid. The sensor is best suited to flow rates between 1 and 30 liters per minute – flow rates below one liter per minute tend not to register accurately.

For flow rates less than 6 liters per minute, we recommend looking at the YF-S401 with a higher resolution / lower flow rate.


  • Working Voltage: 5 to 18VDC
  • Max current draw: 15mA @ 5V
  • Working Flow Rate: 1 to 30 Liters/Minute
  • Working Temperature range: 1°C to 80°C
  • Maximum water pressure: 1.75 MPa
  • Output duty cycle: 50% +-10%
  • Output rise time: 0.04us
  • Output fall time: 0.18us
  • Durability: minimum 300,000 cycles
  • Pulses per Liter: 450


In stock (can be backordered)

SKU: SEN-001. Category: . Tags: , , , .
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Additional information

Weight 53 g


  1. :

    What size are the fitting on this?

  2. :

    The threading is 1/2″ NPS on this product

  3. :

    Does this come with the barb fitting for each end? If not, where to buy?

    • :

      Hi Joe,

      This does not include barbed fittings. It has 1/2″ NPS nominal pipe connections, 0.78″ outer diameter, 1/2″ of thread. I am sure a hardware store would have a piece that adapts the thread to a barbed fitting.

  4. :

    Is it food safe?

    • :

      Unfortunately it is not rated as food safe

  5. :

    Is it possible to use this sensor with gasoline?

    • :

      Hi Mark,

      This sensor does not have any formal chemical ratings so we would advise against using it with anything other than water. Please let us know if you have any additional questions!

  6. :

    Is it possible to use this sensor with AIR ?

    • :

      Hi Pierre,

      It would depend on how you are planning to use it… ultimately, it is designed for water. It will spin when blown into, so it will output something with sufficient air flow.

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