Servo Tuner
Note
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Kit purchase
Looking for parts? Check out our all-in-one kits below — packed with components, beginner-friendly guides, and tons of fun.
Name |
Includes Arduino board |
PURCHASE LINK |
|---|---|---|
Elite Explorer Kit |
Arduino Uno R4 WiFi |
|
3 in 1 Ultimate Starter Kit |
Arduino Uno R4 Minima |
Course Introduction
This Arduino project uses a rotary encoder to precisely control a servo motor, allowing you to set its angle from 0° to 180° in adjustable steps.
An OLED display provides real-time feedback, showing the current servo angle and step size, while a button on the encoder lets you switch between fine and coarse adjustments.
This interactive setup demonstrates digital input for accurate motor positioning and live data display.
Note
If this is your first time working with an Arduino project, we recommend downloading and reviewing the basic materials first.
Required Components
In this project, we need the following components:
SN |
COMPONENT INTRODUCTION |
QUANTITY |
PURCHASE LINK |
|---|---|---|---|
1 |
Arduino UNO R4 WIFI |
1 |
|
2 |
USB Type-C cable |
1 |
|
3 |
Breadboard |
1 |
|
4 |
Wires |
Several |
|
5 |
Digital Servo Motor |
1 |
|
6 |
Rotary Encoder Module |
1 |
|
7 |
OLED Display Module |
1 |
Wiring
Common Connections:
Digital Servo Motor
Connect to breadboard’s positive power bus.
Connect to breadboard’s negative power bus.
Connect to 4 on the Arduino.
Rotary Encoder Module
SW: Connect to 9 on the Arduino.
DT: Connect to 10 on the Arduino.
CLK: Connect to 11 on the Arduino.
GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.
OLED Display Module
SDA: Connect to A4 on the Arduino.
SCK: 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 Adafruit SSD1306 and Adafruit GFX and install it.
Don’t forget to select the board(Arduino UNO R4 Minima/WIFI) and the correct port before clicking the Upload button.
#include <Servo.h> // Include servo motor control library
#include <Wire.h> // Include I2C communication library
#include <Adafruit_GFX.h> // Include core graphics library
#include <Adafruit_SSD1306.h>// Include SSD1306 OLED display library
// OLED display parameters
#define SCREEN_WIDTH 128 // OLED display width in pixels
#define SCREEN_HEIGHT 64 // OLED display height in pixels
#define OLED_RESET -1 // No hardware reset pin used
#define SCREEN_ADDR 0x3C // I2C address for OLED display
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
// Rotary encoder pins
#define ENCODER_CLK 11 // Encoder output A (CLK)
#define ENCODER_DT 10 // Encoder output B (DT)
#define ENCODER_SW 9 // Encoder button switch (SW)
// Servo control pin
#define SERVO_PIN 3 // Servo signal pin
Servo myServo; // Create servo object
int angle = 90; // Initial servo angle (0-180)
int stepSize = 1; // Rotation step: 1°, 5°, or 10°
int lastClkState; // Previous state of CLK for edge detection
int lastSwState; // Previous state of SW for debounce
unsigned long lastDebounce = 0;
const unsigned long DEBOUNCE_MS = 50; // Debounce time in milliseconds
void setup() {
// Initialize encoder pins with internal pull-ups
pinMode(ENCODER_CLK, INPUT_PULLUP);
pinMode(ENCODER_DT, INPUT_PULLUP);
pinMode(ENCODER_SW, INPUT_PULLUP);
Serial.begin(9600); // Start serial communication for debugging
myServo.attach(SERVO_PIN); // Attach servo to control pin
myServo.write(angle); // Move servo to starting angle
// Initialize OLED display and halt if failed
if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDR)) {
Serial.println("SSD1306 allocation failed");
while (true); // Stop execution on failure
}
display.clearDisplay(); // Clear the buffer
display.display(); // Display cleared buffer
// Read initial encoder states
lastClkState = digitalRead(ENCODER_CLK);
lastSwState = digitalRead(ENCODER_SW);
updateDisplay(); // Draw the initial UI
}
void loop() {
// Detect rotation on rising edge of CLK
int clkState = digitalRead(ENCODER_CLK);
if (clkState != lastClkState && clkState == HIGH) {
// Determine direction using DT
if (digitalRead(ENCODER_DT) != clkState) angle = max(0, angle - stepSize);
else angle = min(180, angle + stepSize);
myServo.write(angle); // Move servo to new angle
updateDisplay(); // Update the display
}
lastClkState = clkState;
// Detect button press with debounce
int swState = digitalRead(ENCODER_SW);
if (swState != lastSwState) {
unsigned long now = millis();
if (now - lastDebounce > DEBOUNCE_MS && swState == LOW) {
// Cycle step sizes: 1 -> 5 -> 10
if (stepSize == 1) stepSize = 5;
else if (stepSize == 5) stepSize = 10;
else stepSize = 1;
updateDisplay(); // Refresh display after change
}
lastDebounce = now;
}
lastSwState = swState;
}
// Draw UI elements on OLED display
void updateDisplay() {
// Energy bar region (0-20px)
display.fillRect(0, 0, SCREEN_WIDTH, 20, BLACK);
display.drawRect(0, 0, SCREEN_WIDTH, 20, WHITE);
int barWidth = map(angle, 0, 180, 0, SCREEN_WIDTH);
if (barWidth > 2) display.fillRect(1, 1, barWidth - 2, 18, WHITE);
// Tick marks and labels (20-32px)
display.fillRect(0, 20, SCREEN_WIDTH, 12, BLACK);
display.setTextSize(1);
display.setTextColor(WHITE);
int ticks[] = {0, 30, 60, 90, 120, 150, 180};
for (int deg : ticks) {
int x = map(deg, 0, 180, 0, SCREEN_WIDTH);
display.drawLine(x, 20, x, 24, WHITE);
char buf[4]; snprintf(buf, sizeof(buf), "%d", deg);
int16_t tbx, tby; uint16_t tbw, tbh;
display.getTextBounds(buf, 0, 0, &tbx, &tby, &tbw, &tbh);
display.setCursor(x - tbw/2, 25);
display.print(buf);
}
// Info region (32-64px)
display.fillRect(0, 32, SCREEN_WIDTH, 32, BLACK);
int baseY = 34;
// Draw "Angle" label
display.setTextSize(1);
const char* lblA = "Angle";
int16_t ax, ay; uint16_t aw, ah;
display.getTextBounds(lblA, 0, 0, &ax, &ay, &aw, &ah);
display.setCursor(32 - aw/2, baseY);
display.print(lblA);
// Draw numeric angle value
char valA[4]; snprintf(valA, sizeof(valA), "%d", angle);
display.setTextSize(2);
int16_t vx, vy; uint16_t vw, vh;
display.getTextBounds(valA, 0, 0, &vx, &vy, &vw, &vh);
int valX = 32 - vw/2;
int valY = baseY + ah + 4;
display.setCursor(valX, valY);
display.print(valA);
// Hollow degree symbol next to angle
int r = max(1, vh / 6);
display.drawCircle(valX + vw + r + 1,
valY + vh/2 - r,
r, WHITE);
// Draw "Step" label
display.setTextSize(1);
const char* lblS = "Step";
int16_t sx, sy; uint16_t sw_, sh;
display.getTextBounds(lblS, 0, 0, &sx, &sy, &sw_, &sh);
display.setCursor(96 - sw_/2, baseY);
display.print(lblS);
// Draw numeric step value
char valS[4]; snprintf(valS, sizeof(valS), "%d", stepSize);
display.setTextSize(2);
display.getTextBounds(valS, 0, 0, &sx, &sy, &sw_, &sh);
int sX = 96 - sw_/2;
display.setCursor(sX, valY);
display.print(valS);
// Hollow degree symbol next to step
int r2 = max(1, sh / 6);
display.drawCircle(sX + sw_ + r2 + 1,
valY + sh/2 - r2,
r2, WHITE);
display.display(); // Send buffer to screen
}