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Arduino - Automatic Irrigation System
The automatic irrigation system is a part of the smart garden. In this tutorial, We are going to learn how to make an automatic irrigation system for the garden using Arduino, a soil moisture sensor, relay, and pump. In detail:
- When soil moisture is dry, Arduino automatically controls a relay to turn a pump on to water plants.
- When soil moisture is wet, Arduino automatically controls a relay to turn a pump off.
Hardware Required
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some links in this section are Amazon affiliate links. If you make a purchase through these links, we may earn a commission at no extra cost to you.
Additionally, some links direct to products from our own brand, DIYables.
Additionally, some links direct to products from our own brand, DIYables.
About soil moisture sensor and Pump
If you do not know about pump and soil moisture sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:
- Arduino - Soil Moisture Sensor tutorial
- Arduino - Controls Pump tutorial
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
Arduino Code
/*
* Created by ArduinoGetStarted.com
*
* This example code is in the public domain
*
* Tutorial page: https://arduinogetstarted.com/tutorials/arduino-automatic-irrigation-system
*/
#define RELAY_PIN 2 // Arduino pin that connects to relay
#define MOISTURE_PIN A0 // Arduino pin that connects to AOUT pin of moisture sensor
#define THRESHOLD 530 // 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(500);
}
Quick Steps
- Do calibration to determine the wet-dry THRESHOLD, see Arduino - Calibrates Soil Moisture Sensor
- Update the calibrated THRESHOLD value in the code
- Open Serial Monitor on Arduino IDE
- Upload the code to Arduino
- See 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
Read the line-by-line explanation in the comment lines of the source code!
Video Tutorial
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