ESP32 - Water Sensor - Pump
In this tutorial, we will learn how to use an ESP32 to activate a pump for draining water when it is detected by a water sensor. In other words, we will be discovering how to create an automatic drainage system using an ESP32, a water sensor, and a pump
Hardware Used In This Tutorial
Or you can buy the following sensor kits:
1 | × | DIYables Sensor Kit (30 sensors/displays) | |
1 | × | DIYables Sensor Kit (18 sensors/displays) |
Introduction to Water Sensor and Pump
If you do not know about water sensor and pump (pinout, how it works, how to program ...), learn about them in the following tutorials:
- ESP32 - Water Sensor tutorial
- ESP32 - controls pump tutorial
How the Automatic Drainage System Works
ESP32 periodically reads the value from the water sensor, then:
- If the value is greater than a pre-defined threshold, ESP32 turns on the relay to activate the pump.
- Otherwise, ESP32 turns off the pump.
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.
ESP32 Code
Quick Instructions
- If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
- Do the wiring as above image.
- Connect the ESP32 board to your PC via a micro USB cable
- Open Arduino IDE on your PC.
- Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
- Copy the above code and open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to ESP32
- Put the water sensor into the water
- See the pump's state
Code Explanation
Read the line-by-line explanation in comment lines of source code!
※ NOTE THAT:
This tutorial uses the analogRead() function to read values from an ADC (Analog-to-Digital Converter) connected to a water sensor. The ESP32 ADC is good for projects that do NOT need high accuracy. However, for projects that need precise measurements, please note:
- The ESP32 ADC is not perfectly accurate and might need calibration for correct results. Each ESP32 board can be a bit different, so you need to calibrate the ADC for each individual board.
- Calibration can be difficult, especially for beginners, and might not always give the exact results you want.
For projects that need high precision, consider using an external ADC (e.g ADS1115) with the ESP32 or using an Arduino, which has a more reliable ADC. If you still want to calibrate the ESP32 ADC, refer to ESP32 ADC Calibration Driver
Video Tutorial
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