NEW PRODUCT – Liquid Flow Meter – Brass 1/2 NPT Threaded


NEW PRODUCT – Liquid Flow Meter – Brass 1/2 NPT Threaded. Measure liquid/water flow for your solar, computer cooling, or gardening project using this handy basic flow meter. This sensor sit in line with your water line, and uses a pinwheel sensor to measure how much liquid has moved through it. The pinwheel has a little magnet attached, and there’s a hall effect magnetic sensor on the other side of the brass tube that can measure how many spins the pinwheel has made through the metal wall. This method allows the sensor to stay safe and dry.


The sensor comes with three wires: red (5-18VDC power), black (ground) and yellow (Hall effect pulse output). By counting the pulses from the output of the sensor, you can easily track fluid movement: each pulse is approximately 2 milliliters. Note this isn’t a precision sensor, and the pulse rate does vary a bit depending on the flow rate, fluid pressure and sensor orientation. It will need careful calibration if better than 10% precision is required. However, its great for basic measurement tasks!

We have an example Arduino sketch that can be used to quickly test the sensor – it will calculate the approximate quantity of fluid in liters and display on an LCD or the serial monitor.


  • Working Voltage: 5 to 18VDC
  • Max current draw: 15mA @ 5V
  • Working Flow Rate: 1 to 30 Liters/Minute
  • Working Temperature range: -20°C to 80°C
  • Working Humidity Range: 35%-80% RH
  • Maximum water pressure: 1.75 MPa
  • Output duty cycle: 50% +-10%
  • Output rise time: 0.04us
  • Output fall time: 0.18us
  • Flow rate pulse characteristics: Frequency (Hz) = 8.1 * Flow rate (L/min) – 3
  • Pulses per Liter: 485
  • Durability: minimum 300,000 cycles


  • 1/2″ nominal pipe connections, 0.78″ outer diameter, 1/2″ of thread
  • Size: 2.65″ x 1.0″ x 1.4″

In stock and shipping now!

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  1. Will you be getting these in 3/4" or 1"?

  2. we’ll likely add more sizes over time!

  3. It is a threaded female end on the other side? We only see the male 1/2″ NPT thread.
    Also, what is the advantage over the plastic version (ID 828)?

  4. +1 for 3/4″, 1″

  5. Oh, if you can get ones that are solder in it’d be awesome too.

  6. Are these suitable for water only, or can they be used for other liquids that might require some measure of solvent resistance (e.g. vodka)?

  7. @norm, it is a threaded female end on the other side, the brass version is more durable.
    @ranger9, should be fine – but these are not food rated.

  8. Durability seems a bit low. At 300,000 cycles (which I assume is
    pulses output) and 485 pulses/liter that’s only 619 liters. If you
    were to use this to monitor a top loading washing machine at 40
    gallons per load, the sensor is spec-ed to last < 5 loads!

  9. @JIm: we think its actually much greater than 300k but we’re trying to get a formal data/specsheet.

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