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Arduino - Rain Sensor - Relay
We are going to learn how to:
- If the rain is detected, turn relay on
- If the rain is not detected, turn relay off
By connecting relay to light bulb, led strip, motor or actuator... We can use the rain sensor to control light bulb, led strip, motor or actuator...
Hardware Required
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Please note: These are Amazon affiliate links. If you buy the components through these links, We will get a commission at no extra cost to you. We appreciate it.
About Relay and Rain Sensor
If you do not know about relay and rain sensor (pinout, how it works, how to program ...), learn about them in the following tutorials:
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-relay
*/
#define RAIN_SENSOR_PIN A0 // Arduino pin connected to the OUTPUT pin of rain sensor
#define RELAY_PIN A2 // Arduino pin connected to the IN pin of 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 arduino pin to input mode
pinMode(RELAY_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(RELAY_PIN, HIGH); // turn on
}
else
if (prev_rain_state == HIGH && rain_state == LOW) { // pin state change: HIGH -> LOW
Serial.println("Rain stopped!");
digitalWrite(RELAY_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
- Move your hand in front of sensor
- See the change of relay's state
Code Explanation
Read the line-by-line explanation in comment lines of source code!
Video Tutorial
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