Measuring water flow using YF-S201 Flow meter

The EzloPi smart devices provide automation through simple, customizable use with our open-source EzloPi platform, making daily life easier and improving human-machine interactions.

Before moving into this example, it is very important to know about the device registration, provisioning and converting the ESP32 device into an EzloPi device along with knowledge of Web Flasher, MiOS Mobile Application for Android/iOS and the MiOS Web Application.

1. About this example

This project aims to integrate a YF-S201 flow meter with the EzloPi device to enable accurate monitoring and control of liquid flow in various applications. By interfacing these two components, users can track flow rates in real-time and implement automated actions based on predefined thresholds or patterns using meshbots. Integration of the EzloPi device with the YF-S201 flow meter allows for precise measurement of liquid flow, enhancing efficiency and enabling intelligent decision-making.

Through this project, users can leverage the combined capabilities of both devices to optimize processes, detect anomalies, and improve overall system performance. The seamless integration of the YF-S201 flow meter with the EzloPi device offers a versatile solution suitable for a wide range of monitoring applications.

2. Project Video Demonstration

Welcome to the project demonstration video section. The following video showcases the key aspects of Measuring water flow using YF-S201 Flow meter, providing a visual walkthrough of its implementation.

Project Video Demonstration

3. Circuit Setup & Interfacing

The following components are required for interfacing with the EzloPi device:

  • ESP32 as an EzloPi smart device.
  • YF-S201 Flow Meter.

The wiring diagram of ESP32 30 pin is represented as follows:

The following connections are made in order to complete the circuit setup:

From ESP32 to YF-S201 Flowmeter:


4. Interfacing the Flow meter with the EzloPi Web Flasher:

1. First setup your MiOS account by visiting and set up your device/hardware by visiting

  1. Log in using the credentials which you just set earlier while signing up.
  1. Now, click on the Connect Device button and a pop-up window will appear.
  1. Now, select COM Port to which your ESP32 device is connected. In our case, the COM3 port is used.

Click Connect

  1. If you are new to this and it's your first time configuring, select Create new Device ID. Click on the Configure Wifi button. Enter Wifi SSID and Wifi Password.
  2. In the Device Configuration, tab click on PWM.
  1. A PWM window will open for inputting the following parameters:
  • Set a Device Name of your choosing. In our case, we set it to Flowmeter.
  • Set Device Subtype to YFS201 Flowmeter.
  • Set the PWM_GPIO to 5.
  • Set the Frequency from the given Frequency slider.
  • Set the Resolution to 8 bits.
  • Set the Duty Cycle from the given Duty Cycle slider.
  • Now Click the Apply button.
  • After clicking the apply button you can see a table of your setting in the device configuration tab.
  • Press the Flash Device button.
  1. A window will appear on the bottom right side of the screen displaying “Please press BOOT button while flashing begins.”
  1. Hold the BOOT button down until the next window appears on the bottom right side of the screen which says “Installation prepared. Please release the boot button now.”
  1. Release the BOOT button from your ESP32 when this pop-up on the bottom right window appears.
  1. After some time, a popup will appear saying Device Flashed Successfully! This means that your device has been set up successfully.

5. MiOS App

You can download the MIOS Android app from the Google Play Store and Apple App Store.

Google PlayApple App Store

  1. After downloading the app, proceed to install the application and open it.
  1. Using the MIOS mobile application, create a new Ezlo Cloud account using the sign-up option. If you already have an account, you may proceed to log in.
  1. After successfully logging in, you will be able to see the number of controllers connected such as a lamp, fan, or any other device in the MiOS app. Tap on any controller of your desired ID:
  1. You will be able to see the status of your controller whether it is online or offline. Access the device dashboard, and tap the device. The following view of the dashboard will appear:
  1. After opening the MiOS mobile dashboard, you will be able to see the tile of your connected device. As seen above, the flow meter tile is displayed which shows how much water is flowing.

5. MiOS Web Dashboard

  1. After configuring the controller with the EzloPi web flasher, head to
  1. Use the same credentials to log in that you used for configuring the controller with the web flasher.
  1. After opening the MiOS mobile dashboard, you will be able to see the tile of your connected device. As seen above, the flow meter tile is displayed which shows how much water is flowing.
Buy Components

eZlopie Products A single-channel 5V relay module $00.00

eZlopie Products Momentary switch $00.00

eZlopie Products Level Shifter Module (BSS138) $00.00

eZlopie Products ESP32

eZlopie Products AC Lamp and Holder