Arduino - Control Fan

Arduino can not only turn on/off the fan but also control the fan's speed.

In this tutorial, we are going to learn how to turn on/off a fan using Arduino. Controlling the fan's speed will be presented in another tutorial.

Hardware Required

1	×	Arduino UNO or Genuino UNO
1	×	USB 2.0 cable type A/B
1	×	Relay
1	×	12V DC Cooling Fan
1	×	(Alternative) 5V DC Cooling Fan
1	×	12V Power Adapter
1	×	DC Power Jack
1	×	Jumper Wires
1	×	(Optional) 9V Power Adapter for Arduino
1	×	(Recommended) Screw Terminal Block Shield for Arduino Uno
1	×	(Optional) Transparent Acrylic Enclosure For Arduino Uno

Or you can buy the following sensor kit:

DIYables Sensor Kit 30 types, 69 units

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 DC Fan

Pinout

A DC fan usually has two pins:

Negative (-) pin (black): needs to be connected to the negative wire of DC power supply
Positive (+) pin (red): needs to be connected to the positive wire of DC power supply

image source: diyables.io

The voltage of the DC power supply should be equal to the voltage specified by the fan. In this tutorial, we will use 12VDC and 5VDC fans.

How to Control Fan

If DC fan is powered by 12V/5V power supply, it run with full speed.
If DC fan is powered by 12V/5V PWM signal, The fan's speed can be controlled.

In this tutorial, we are going to learn how to turn on/off a fan using Arduino. Controlling the fan's speed will be presented in another tutorial. To turn on/off a fan, we need to use a relay in between Arduino and fan. Arduino can turn on/off the fan via the relay. If you do not know about relay (pinout, how it works, how to program ...), learn about relay in the Arduino - Relay tutorial

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Arduino Code

The below code repeatedly turns the fan ON in five seconds and OFF in five seconds,

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-controls-fan */ // constants won't change const int RELAY_PIN = 3; // the Arduino pin, which connects to the IN pin of relay // the setup function runs once when you press reset or power the board void setup() { // initialize digital pin D3 as an output. pinMode(RELAY_PIN, OUTPUT); } // the loop function runs over and over again forever void loop() { digitalWrite(RELAY_PIN, HIGH); // turn on fan 5 seconds delay(5000); digitalWrite(RELAY_PIN, LOW); // turn off fan 5 seconds delay(5000); }

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
See the fan's state

Code Explanation

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

Video Tutorial

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