ESP32 - Soil Moisture Sensor Pump

In this tutorial, We are going to learn how to use the ESP32 to control the pump according to the value read from the capacitive soil moisture sensor.

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×USB Cable Type-C
1×Capacitive Soil Moisture Sensor
1×Relay
1×12V Pump
1×Vinyl Tube
1×12V Power Adapter
1×(Optional) DC Power Jack
1×Breadboard
1×Jumper Wires
1×(Recommended) ESP32 Screw Terminal Adapter

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
Disclosure: some of these links are affiliate links. We may earn a commission on your purchase at no extra cost to you. We appreciate it.

Buy Note: Numerous capacitive soil moisture sensors available in the market are of poor quality, regardless of the version. We strongly advise purchasing the sensor from the DIYables brand via the link above; we conducted tests, and it performed reliably.

Introduction to 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:

How It Works

ESP32 periodically reads the value from the capacitive soil moisture sensor. Based on the soil moisture value, it will take the following actions:

  • If the soil moisture value is below a threshold, ESP32 automatically activates a relay to turn a pump on.
  • Otherwise, ESP32 automatically deactivates a relay to turn a pump off.

Wiring Diagram

ESP32 soil moisture sensor 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

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-soil-moisture-sensor-pump */ #define RELAY_PIN 17 // ESP32 pin GPIO17 that connects to relay #define MOISTURE_PIN 36 // ESP32 pin GPIO36 (ADC0) that connects to AOUT pin of 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 soild moisture sensor if (value > THRESHOLD) { Serial.print("The soil moisture is DRY => activate pump"); digitalWrite(RELAY_PIN, HIGH); } else { Serial.print("The soil moisture is WET=> deactivate the pump"); digitalWrite(RELAY_PIN, LOW); } Serial.print(" ("); Serial.print(value); Serial.println(")"); delay(1000); }

Quick Instructions

COM6
Send
The soil moisture is DRY => activate the pump The soil moisture is DRY => activate the pump The soil moisture is DRY => activate the pump The soil moisture is DRY => activate the pump The soil moisture is WET=> deactivate the pump The soil moisture is WET=> deactivate the pump The soil moisture is WET=> deactivate the pump The soil moisture is WET=> deactivate the pump
Autoscroll Show timestamp
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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