Arduino Project
Mini Fan 5.0
Course Introduction
In this lesson, you’ll build a smart fan controller using a rotary encoder, a servo, an LCD, and PWM motor control. Turning the encoder adjusts the servo angle, pressing the button switches between fan speed levels, and the LCD displays real-time angle and gear information.
Note
If this is your first time working with an Arduino project, we recommend downloading and reviewing the basic materials first.
1.1 Install Arduino IDE(Important)
1.2 Introduction of Arduino IDE
Required Components
In this project, we need the following components:
Wiring
Common Connections:
TA6586 - Motor Driver Chip
BI: Connect to 6 on the Arduino.
FI: Connect to 5 on the Arduino.
GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.
DC Motor
GND: Connect to TA6586 B0.
VCC: Connect to TA6586 F0.
Rotary Encoder Module
CLK: Connect to 12 on the Arduino.
DT: Connect to 11 on the Arduino.
SW: Connect to 10 on the Arduino.
GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.
Digital Servo Motor
Connect to breadboard’s positive power bus.
Connect to breadboard’s negative power bus.
Connect to 3 on the Arduino.
I2C LCD 1602
SDA: Connect to A4 on the Arduino.
SCL: Connect to A5 on the Arduino.
GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.
Writing the Code
Note
You can copy this code into Arduino IDE.
To install the library, use the Arduino Library Manager and search for LiquidCrystal I2C and install it.
Don’t forget to select the board(Arduino UNO R4 WIFI) and the correct port before clicking the Upload button.
#include
#include
#include
// LCD using I2C (address may be 0x27 or 0x3F)
LiquidCrystal_I2C lcd(0x27, 16, 2);
// Fan output pins
const int fiPin = 5;
const int biPin = 6;
// Servo
Servo servo;
const int servoPin = 3;
// Rotary encoder pins
const int CLK = 12; // rotation signal A
const int DT = 11; // rotation signal B
const int SW = 10; // push button (LOW when pressed)
// Encoder state tracking
int lastCLK = HIGH;
unsigned long lastPress = 0;
// Servo angle settings
int angle = 90;
const int angleMin = 45;
const int angleMax = 135;
const int angleStep = 5; // rotate encoder = change 5 degrees
// Fan gear levels (0 = off)
int gear = 0;
int fanSpeed = 0;
// LCD update tracking
int lastAngle = -1;
int lastGear = -1;
void setup() {
// Motor pins
pinMode(fiPin, OUTPUT);
pinMode(biPin, OUTPUT);
// Encoder pins with pull-ups for stable signals
pinMode(CLK, INPUT_PULLUP);
pinMode(DT, INPUT_PULLUP);
pinMode(SW, INPUT_PULLUP);
// Servo setup
servo.attach(servoPin);
servo.write(angle);
// LCD setup
lcd.init();
lcd.backlight();
lcd.clear();
}
void loop() {
// ----------------------------------------------------
// Read rotary encoder rotation
// Only allowed when fan gear > 0 (fan ON)
// Falling edge of CLK gives stable step detection
// ----------------------------------------------------
int currentCLK = digitalRead(CLK);
if (currentCLK == LOW && lastCLK == HIGH) {
if (gear > 0) { // servo locked when gear = 0 (fan OFF)
// Determine rotation direction
if (digitalRead(DT) == HIGH) {
angle += angleStep; // clockwise
} else {
angle -= angleStep; // counterclockwise
}
// Keep angle within safe limits
angle = constrain(angle, angleMin, angleMax);
servo.write(angle);
}
}
lastCLK = currentCLK;
// ----------------------------------------------------
// Change fan gear (0 → 3) when encoder button pressed
// ----------------------------------------------------
if (digitalRead(SW) == LOW) {
if (millis() - lastPress > 300) { // debounce
gear++;
if (gear > 3) gear = 0; // loop back
lastPress = millis();
}
}
// ----------------------------------------------------
// Convert gear level to fan PWM value
// ----------------------------------------------------
if (gear == 0) fanSpeed = 0;
if (gear == 1) fanSpeed = 85;
if (gear == 2) fanSpeed = 170;
if (gear == 3) fanSpeed = 255;
analogWrite(biPin, fanSpeed);
analogWrite(fiPin, 0); // fixed LOW direction
// ----------------------------------------------------
// Update LCD only when values change
// Reduces I2C traffic → prevents encoder lag
// ----------------------------------------------------
if (angle != lastAngle || gear != lastGear) {
lcd.setCursor(0, 0);
lcd.print("Angle:");
lcd.print(angle);
lcd.print(" ");
lcd.setCursor(0, 1);
lcd.print("Gear:");
lcd.print(gear);
lcd.print(" PWM:");
lcd.print(fanSpeed);
lcd.print(" ");
lastAngle = angle;
lastGear = gear;
}
}