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G3-4 Water Flow sensor

Water flow sensor consists of a plastic valve body, a water rotor, and a hall-effect sensor. When water flows through the rotor, rotor rolls. Its speed changes with different rate of flow. The hall-effect sensor outputs the corresponding pulse Signal.


Mini. Wokring VoltageDC 4.5V
Max. Working Current15mA(DC 5V)
Working Voltage5V~24V
Flow Rate Range1~60L/min
Load Capacity≤10mA(DC 5V)
Operating Temperature≤80℃
Liquid Temperature≤120℃
Operating Humidity35%~90%RH
Water Pressure≤2.0MPa
Storage Temperature-25℃~+80℃
Storage Humidity25%~95%RH

Mechanic Dimensions

Sensor Components

1 Valve body 1 PA66+33%glass fiber
2 Stainless steel bead 1 Stainless steel SUS304
3 Axis 1 Stainless steel SUS304
4 Impeller 1 POM
5 Ring magnet 1 Ferrite
6 Middle ring 1 PA66+33%glass fiber
7 O-seal ring 1 Rubber
8 Electronic seal ring 1 Rubber
9 Cover 1 PA66+33%glass fiber
10 Screw 4 Stainless steel SUS304
11 Cable 1 1007 24AWG

Usage Example

Note: This example is abstracted from the forum, which was done by Charles Gantt. Thanks for his contribution.Let's see how it works.

Reading Water Flow rate with Water Flow Sensor

This is part of a project I have been working on and I thought I would share it here since there have been a few threads on how to read water flow rate in liters per hour using the Water Flow Sensor found in the Seeed Studio Depo. It uses a simple rotating wheel that pulses a hall effect sensor. By reading these pulses and implementing a little math, we can read the liquids flow rate accurate to within 3%. The threads are simple G3/4 so finding barbed ends will not be that hard.

Hardware Installation

You will need Seeeduino / Arduino ,Water Flow Sensor,10K resistor,a breadboard and some jumper wires.

Wiring up the Water Flow Sensor is pretty simple. There are 3 wires: Black, Red, and Yellow. Black to the Seeeduino's ground pin Red to Seeeduino's 5v pin The yellow wire will need to be connected to a 10k pull up resistor.and then to pin 2 on the Seeeduino.

Here is a fritzing diagram I made to show you how to wire it all up.

Once you have it wired up you will need to upload the following code to your Seeeduino. Once it is uploaded and you have some fluid flowing through the Water Flow Sensor, you can open the serial monitor and it will display the flow rate, refreshing every second.


// reading liquid flow rate using Seeeduino and Water Flow Sensor from
// Code adapted by Charles Gantt from PC Fan RPM code written by Crenn
// http:/

volatile int NbTopsFan; //measuring the rising edges of the signal
int Calc;
int hallsensor = 2; //The pin location of the sensor

void rpm () //This is the function that the interupt calls
NbTopsFan++; //This function measures the rising and falling edge of the

hall effect sensors signal
// The setup() method runs once, when the sketch starts
void setup() //
pinMode(hallsensor, INPUT); //initializes digital pin 2 as an input
Serial.begin(9600); //This is the setup function where the serial port is

attachInterrupt(0, rpm, RISING); //and the interrupt is attached
// the loop() method runs over and over again,
// as long as the Arduino has power
void loop ()
NbTopsFan = 0; //Set NbTops to 0 ready for calculations
sei(); //Enables interrupts
delay (1000); //Wait 1 second
cli(); //Disable interrupts
Calc = (NbTopsFan * 60 / 5.5); //(Pulse frequency x 60) / 5.5Q, = flow rate

in L/hour
Serial.print (Calc, DEC); //Prints the number calculated above
Serial.print (" L/hour\r\n"); //Prints "L/hour" and returns a new line

You can refer our forum for more details about Reading Water Flow rate with Water Flow Sensor.

Wiring Diagram

The external diameter of thread the connections use is 1.4mm.

Output Table

Pulse frequency (Hz) in Horizontal Test= 5.5Q, Q is flow rate in L/min. (Results in +/- 3% range)

Output pulse high levelSignal voltage >4.5 V( input DC 5 V)
Output pulse low levelSignal voltage <0.5V( input DC 5V)
Precision3% (Flow rate from 1L/min to 10L/min)
Output signal duty cycle40%~60%


Here is the Sensors FAQ, people can go here to find questions and answers for this kind of products.

What materials is water flow sensor made of?

Nylon with fiber, avoiding strong acid and strong base.

Is the water flow sensor safe for drinking water?

Yeah, it has been used on drinking machine.


It's a pity that we don't have any demo about G3/4 Water Flow Sensor in the Recipe yet.

Post your awesome project about G3/4 Water Flow Sensor to win $100 Coupon!. Please feel free to contact us: [email protected]

Here we introduce some projects about Grove-Water Sensor.

What is Grove - Water Sensor

This water sensor module is part of the Twig system.You can use it with the analog pins to detect the amount of water induced contact between the grounded and sensor traces.

It works by having a series of exposed traces connected to ground and interlaced between the grounded traces are the sens traces.

The sensor traces have a weak pull-up resistor of 1 MΩ. The resistor will pull the sensor trace value high until a drop of water shorts the sensor trace to the grounded trace.

This circuit will work with the digital I/O pins of your Arduino.

Arduino Plant Warden

This project uses Grove - Water Sensor to create a simple but effective solution to watering plants.

How it works:

  • Display readouts of water sensor and temperature sensor on OLED screen

  • Send alert and activate a pump driver when water is under threshold.

  • Supply the variation in color by 10 RGB LEDs.

I want to make it.

More Awesome Projects by Water Sensor

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