ESP32 - Rain Sensor - Buzzer

In this tutorial, We will explore the process of utilizing ESP32 for rain detection and creating an alarm system with a buzzer.

Hardware Used In This Tutorial

1	×	ESP-WROOM-32 Dev Module
1	×	USB Cable Type-C
1	×	Rain Sensor
1	×	Relay
1	×	12V Active Buzzer
1	×	12V Power Adapter
1	×	DC Power Jack
1	×	Jumper Wires
1	×	(Recommended) Screw Terminal Expansion Board for ESP32

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

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Introduction to 12V Buzzer and Rain Sensor

Unfamiliar with 12V buzzer and rain sensor, including their pinouts, functionality, and programming? Explore comprehensive tutorials on these topics below:

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-rain-sensor-buzzer */ #define RAIN_SENSOR_PIN 25 // The ESP32 pin GPIO25 connected to the sound sensor #define BUZZER_PIN 26 // The ESP32 pin GPIO26 connected to the relay int rain_state = LOW; // current state of rain sensor's pin int prev_rain_state = LOW; // previous state of rain sensor's pin void setup() { Serial.begin(9600); // initialize serial pinMode(RAIN_SENSOR_PIN, INPUT); // set ESP32 pin to input mode pinMode(BUZZER_PIN, OUTPUT); // set ESP32 pin to output mode } void loop() { prev_rain_state = rain_state; // store old state rain_state = digitalRead(RAIN_SENSOR_PIN); // read new state if (prev_rain_state == LOW && rain_state == HIGH) { // pin state change: LOW -> HIGH Serial.println("Rain detected!"); digitalWrite(BUZZER_PIN, HIGH); // turn on buzzer } else if (prev_rain_state == HIGH && rain_state == LOW) { // pin state change: HIGH -> LOW Serial.println("Rain stopped!"); digitalWrite(BUZZER_PIN, LOW); // turn off buzzer } }

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.
Connect ESP32 to PC via USB cable
Open Arduino IDE, select the right board and port
Copy the above code and open with Arduino IDE
Click Upload button on Arduino IDE to upload code to ESP32
Move your hand in front of sensor
Listen to 12V buzzer's sound

Code Explanation

Read the line-by-line explanation in comment lines of source code!

Video Tutorial

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