water flow sensor

Many flow systems are automated nowadays, making flow sensors vital components in ensuring safety and measurement accuracy in a plant. These crucial devices are small enough to be embedded in larger electronics. They are also affordable and reliable. If you are looking for a water flow sensor in the market to fuse with your system, then you have to ensure that you’ve chosen the right flow sensor for the right application. 

Technology has made it possible to enhance not just the size of these flow sensors but functionality too. The earlier technologies of flow sensors were used to measure fluid in cm units. Sensors are now more advanced and can measure on a scale of nm. Flow sensors have also evolved to solve many electrical and electronic engineering challenges. Operators can now use flow sensors to determine furnace temperature, ambient light intensity, calculating ambient light intensity, and so much more. They are great tools for finding out the flow rate of a fluid or liquid. 

In this article, we are going to explore the working principle of flow sensors. Before doing that, let’s first help you understand what a flow sensor is. 

What is a Water Flow Sensor?

The amount of water pumped into commercial and residential buildings and huge industrial plants is quite a lot. Requirements are met in public water supply systems by set parameters. Measuring the flow rate of water makes it easy to monitor the amount of water being supplied. Water flow sensors are meant to serve this purpose. 

A water flow sensor is installed at the water source to get an accurate flow rate of water flowing through the system or pipe. This is done to make it easier to calculate the flow rate of water flowing through. The unit used to measure water flow rate is liters per hour or cubic meters.

Working Principle of a Water Flow Sensor 

A water flow sensor is made up of a plastic valve, which passes through water. The device also has a water rotor and a hall effect sensor for sensing and measuring the water flow. Water flowing through the valve spins the rotor. When this happens, the change will affect the speed of the motor. The hall effect sensor will calculate this change as a pulse signal. This allows the water flow rate to be measured. 

The Hall effect represents the entire working principle of a water flow sensor. Based on the principle, the rotation of the rotor causes the conductor to induce an electric charge. The electric current is transverse from induced voltage difference. 

Once the water flowing through the pipe rotates the moving fan, it induces a charge from the spinning rotor. The hall effect sensor measures the induced voltage, and readings are shown on the LCD. The water flow sensor is used to measure all kinds of water, including hot water, warm water, cold water, dirty water, and clean water. 

These types of flow sensors also come in different flow ranges and diameters. Water flow sensors can be interfaced with microcontrollers for better delivery. To fuse microcontroller boards with a water flow sensor for advanced processing, a 16×2 LCD and Breadboard connecting wires are needed. The water flow sensor has to be installed at the water pipe’s opening or the water source inlet. 

There are three wires found inside the flow sensor:

  • Black wire to connect to ground 
  • Red wire to connect with supply voltage
  • Yellow wire to collect output from Hall effect sensor

A power supply voltage of between 5V to 18V DC is needed. 

Water Flow Sensor Applications 

To measure the flow rate of water, a water flow sensor measures the displacement or velocity of water. Besides measuring water flow rate, flow sensors can also measure flow rates of fluids such as milk or beverage. Flow sensors are also applicable in various industries based on their diameters. The commonly used flow sensor is called Paddlewheel, which is used with many fluids and is also cost-effective. 

A positive displacement flow meter is used in applications that don’t have straight pipes at the inlet. A PD flow meter is also ideal for measuring viscous liquids. If you are working with wastewater or dirty water, the ideal flow meter will be magnetic flow meters, provided the fluids are conductive. 


A flow sensor is an ideal flow measurement instrument if you want to get accurate water measurement. Since there are numerous flow sensors with different sizes and diameters, you need to select proper flow sensors based on the application. If you are unsure of which water flow sensor to use in your application, ask the manufacturer for guidance. 

MD: Having difficulty with the right kind of water flow sensor to use with your system? Using the right kind of flow sensor is paramount if you want to achieve accurate measurement. Read on for more information. 

By Anurag Rathod

Anurag Rathod, as a blogger he used to spread all about app-based business, startup solution, on-demand business tips and ideas and so on.

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