Arduino - Rain Sensor - LED

We are going to learn how to:

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B (for USB-A PC)
1×USB 2.0 cable type C/B (for USB-C PC)
1×Rain Sensor
1×LED
1×220 ohm resistor
1×Breadboard
1×Jumper Wires
1×(Recommended) Screw Terminal Block Shield for Arduino Uno
1×(Recommended) Breadboard Shield For Arduino Uno
1×(Recommended) Enclosure For Arduino Uno

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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Additionally, some links direct to products from our own brand, DIYables.

About LED and Rain Sensor

If you do not know about led and rain sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

Arduino Rain Sensor LED 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-rain-sensor-led */ #define RAIN_SENSOR_PIN A0 // Arduino pin connected to the OUTPUT pin of rain sensor #define LED_PIN 7 // Arduino pin connected to LED's pin 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 arduino pin to input mode pinMode(LED_PIN, OUTPUT); // set arduino 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(LED_PIN, HIGH); // turn on } else if (prev_rain_state == HIGH && rain_state == LOW) { // pin state change: HIGH -> LOW Serial.println("Rain stopped!"); digitalWrite(LED_PIN, LOW); // turn off } }

Quick Steps

  • Connect Arduino 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 Arduino
Arduino IDE Upload Code
  • Move your hand in front of sensor
  • See the change of LED's state

Code Explanation

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

Video Tutorial

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