Arduino Project
Mini Fan 4.0
Course Introduction
In this lesson, you’ll create a simple control system using a rotary encoder to steer a servo and adjust fan speed. Turning the encoder changes the servo angle, while pressing the button cycles through multiple fan speed levels.
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.
Writing the Code
Note
You can copy this code into Arduino IDE.
Don’t forget to select the board(Arduino UNO R4 WIFI) and the correct port before clicking the Upload button.
#include
// Fan motor pins
const int fiPin = 5; // fixed LOW in this project
const int biPin = 6; // PWM output to control fan speed
// Servo setup
Servo servo;
const int servoPin = 3; // servo signal pin
// Rotary encoder pins
const int CLK = 12; // main signal: detects rotation steps
const int DT = 11; // direction signal
const int SW = 10; // encoder button (LOW when pressed)
// Variables for encoder reading
int lastCLK = HIGH; // used to detect edge
unsigned long lastPress = 0; // debounce timer for SW
// Servo angle control
int angle = 90; // starting angle
const int angleMin = 45; // left limit
const int angleMax = 135; // right limit
const int angleStep = 2; // angle change per encoder step
// Fan gear control
int gear = 0; // 0~3 speed levels
int fanSpeed = 0; // actual PWM value
void setup() {
// Motor pins
pinMode(fiPin, OUTPUT);
pinMode(biPin, OUTPUT);
// Encoder pins
pinMode(CLK, INPUT);
pinMode(DT, INPUT);
pinMode(SW, INPUT_PULLUP); // button is active LOW
// Servo setup
servo.attach(servoPin);
servo.write(angle);
}
void loop() {
// ===============================
// Read encoder rotation
// ===============================
int currentCLK = digitalRead(CLK);
// Detect the rising edge of CLK (means one "tick")
if (currentCLK != lastCLK && currentCLK == HIGH) {
// Compare DT to decide direction
if (digitalRead(DT) == currentCLK) {
angle += angleStep; // clockwise → angle increases
} else {
angle -= angleStep; // counterclockwise → angle decreases
}
// Keep the servo angle inside safe limits
angle = constrain(angle, angleMin, angleMax);
// Move servo to new angle
servo.write(angle);
}
lastCLK = currentCLK;
// ===============================
// Read encoder button (SW)
// ===============================
// Button pressed (active LOW)
if (digitalRead(SW) == LOW) {
// Simple debounce check
if (millis() - lastPress > 300) {
gear++; // next speed level
if (gear > 3) gear = 0; // wrap around (0→1→2→3→0...)
lastPress = millis();
}
}
// ===============================
// Convert gear level to PWM speed
// ===============================
if (gear == 0) fanSpeed = 0; // fan off
if (gear == 1) fanSpeed = 85; // low
if (gear == 2) fanSpeed = 170; // medium
if (gear == 3) fanSpeed = 255; // high
// ===============================
// Output speed to fan motor
// ===============================
if (fanSpeed > 0) {
analogWrite(biPin, fanSpeed); // send PWM speed
analogWrite(fiPin, 0); // keep opposite pin LOW
} else {
analogWrite(biPin, 0); // stop fan
analogWrite(fiPin, 0);
}
}