YF-S401 Water Flow Rate Sensor


This is a variant of YF-S401 flow rate sensor. This is a flow rate sensor that can be used with Arduino to measure rate of liquid flow through it.

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SKU: MDU-SEN-YF-S401 Category: Tags: ,


This sensor sits in line with your water line and contains a pinwheel sensor to measure how much liquid has moved through it. There’s an integrated magnetic hall effect sensor that outputs an electrical pulse with every revolution. The hall effect sensor is sealed from the water pipe and allows the sensor to stay safe and dry. This one is suitable to detect flow in water dispenser or coffee machine.

  • 6 mm hose is recommended
  • Avoid unit contact with corrosive chemicals
  • The unit must be installed vertically, tilted no more than 5 degrees
  • Liquid temperature should be less than 120 C to avoid damage to unit



  • Operating voltage: 4.5 – 12V
  • Operating Current : <15mA
  • Water resistant : 0.35MPa
  • Operating flow rate : 1 – 5L/min
  • Operating temperature: ?80?C
  • Liquid temperature: ?120?C
  • Operating humidity: 35 – 90% RH
  • Water pressure limit : ? 1.75MPa
  • Internal diameter : 1.2mm
  • Error : ?2L/min
  • Insulation resistance : >100M?
  • Output pulse duty cycle : 50?10%
  • Flow pulse characteristics : (98 * Q) ? 2% Q = L / MIN



VCC (Red)Power sourceConnect to 5V of system
OUT (Yellow or White)Output pulse signalConnect to any digital pin
GND (Black)GroundConnect to GND of system


Files & Documentation

Additional information

Weight30 g
Dimensions60 × 35 × 35 mm