Arduino Nano ESP32 - Automatic Irrigation System
This tutorial instructs you how to use Arduino Nano ESP32, soil moisture sensor, relay, and pump to build an automatic irrigation system for the garden with. Specifically:
- Arduino Nano ESP32 will be used to control the relay in order to switch on the pump when the soil moisture is dry.
- When the soil moisture is wet, Arduino Nano ESP32 will be used to control the relay to turn the pump off.
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you. We appreciate your support.
Buy Note: Many soil moisture sensors available in the market are unreliable, regardless of their version. We strongly recommend buying the sensor from the DIYables brand using the link provided above. We tested it, and it worked reliably.
Overview of soil moisture sensor and Pump
If you are not familiar with pump and soil moisture sensor (including pinout, functioning, programming, etc.), the following tutorials will be helpful:
- Arduino Nano ESP32 - Controls Pump tutorial
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
Arduino Nano ESP32 Code
/*
* This Arduino Nano ESP32 code was developed by newbiely.com
*
* This Arduino Nano ESP32 code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/arduino-nano-esp32/arduino-nano-esp32-automatic-irrigation-system
*/
#define RELAY_PIN D2 // The Arduino Nano ESP32 pin connected to the relay
#define MOISTURE_PIN A2 // The Arduino Nano ESP32 pin connected to the moisture sensor
#define THRESHOLD 2800 // CHANGE YOUR THRESHOLD HERE
void setup() {
Serial.begin(9600);
pinMode(RELAY_PIN, OUTPUT);
}
void loop() {
int value = analogRead(MOISTURE_PIN); // read the analog value from sensor
if (value > THRESHOLD) {
Serial.print("The soil is DRY => turn pump ON");
digitalWrite(RELAY_PIN, HIGH);
} else {
Serial.print("The soil is WET => turn pump OFF");
digitalWrite(RELAY_PIN, LOW);
}
Serial.print(" (");
Serial.print(value);
Serial.println(")");
delay(200);
}
Detailed Instructions
- If you are new to Arduino Nano ESP32, refer to the tutorial on how to set up the environment for Arduino Nano ESP32 in the Arduino IDE.
- Wire the components as shown in the diagram.
- Connect the Arduino Nano ESP32 board to your computer using a USB cable.
- Open Arduino IDE on your computer.
- Choose the correct Arduino Nano ESP32 board, such as (e.g. NodeMCU 1.0 (ESP-12E Module)), and its respective COM port.
- Perform calibration to identify the wet-dry THRESHOLD, as outlined in Arduino Nano ESP32 - Calibrates Soil Moisture Sensor.
- Insert the calibrated THRESHOLD value into the code.
- Launch Serial Monitor on Arduino IDE.
- Upload the code to Arduino Nano ESP32.
- View the result on Serial Monitor.
COM6
The soil is DRY => turn pump ON
The soil is DRY => turn pump ON
The soil is DRY => turn pump ON
The soil is DRY => turn pump ON
The soil is WET => turn pump OFF
The soil is WET => turn pump OFF
The soil is WET => turn pump OFF
The soil is WET => turn pump OFF
Autoscroll
Clear output
9600 baud
Newline
Code Explanation
Check out the line-by-line explanation contained in the comments of the source code!