Distance Measurement with Arduino Using Ultrasonic Sensor & OLED

Introduction

Measurement of Distance is one of the tricky task now a days. there are many methode to measure the distance like scale, feeta and etc but measure the distance using the Electronic is fun. So today wee have made this project , Distance Measurement with Arduino. which can help to make the distance measurement device using Arduino , ultrasonic , and many other components. we have made this and tested, now we will share al the detail which we got to make this project. we have also made a video and uploaded on my youtube channel. for youtube video i have shared the link.

Distance measurement is one of the most popular and practical applications of Arduino in real‑world electronics projects. From obstacle‑avoiding robots and smart parking systems to security alarms and automation, the ability to detect how far an object is plays a vital role. In this article, we will build a complete Arduino‑based distance monitoring system using an ultrasonic sensor, an OLED display, three LEDs, and a buzzer for audible alerts.

This project measures distance using an ultrasonic sensor, displays the measured value clearly on an OLED screen using a large, easy‑to‑read font, and provides visual and sound alerts based on how close an object is. When the distance becomes too small, the buzzer produces a continuous beep, making the system suitable for safety‑critical applications.

we have made a of project in which the same concepts are used, obstacle avoiding robot, Smart Dustbin, human following robot. all these project uses the same concepts. ultrasonic sensor distance measurement.

The project is beginner‑friendly, highly practical, and can be easily customized for different distance ranges and alert behaviors.

Why Use an Ultrasonic Sensor for Distance Measurement?

Ultrasonic sensors are widely used because they are:

Low cost
Easy to interface with Arduino
Accurate for short‑range distance measurement
Independent of lighting conditions

The ultrasonic sensor works by sending high‑frequency sound waves and measuring the time taken for the echo to return. This time is converted into distance using a simple formula.ultrasonic sensor have good accuracy than other sensors like IR sensor. so, we choose this sensor. also, you can buy the ultrasonic sensor. the availableity is very good. Distance Measurement with Arduino is very simple with this sensor.

Project Overview

In this project, the Arduino continuously measures distance using an ultrasonic sensor. The measured distance is then:

Displayed on an OLED screen in large font
Indicated using LEDs (Green, Yellow, Red)
Accompanied by a continuous buzzer alert when the object is too close

Distance Indication Logic

Distance greater than 30 cm → Green LED ON (Safe zone)
Distance between 15 cm and 30 cm → Yellow LED ON (Warning zone)
Distance less than 15 cm → Red LED ON + Continuous Buzzer (Danger zone)

Components Required

To build this project, you will need the following components:

Arduino Uno (or compatible board)
Ultrasonic Sensor (HC‑SR04)
0.96‑inch OLED Display (128×64, I2C)
Green, Yellow, Red LED Module
Buzzer (Active or Passive)
220Ω resistors for LEDs
Breadboard
Jumper wires
USB cable for Arduino

Now we need the right circuit diagram.

Distance Measurement with Arduino Circuit Diagram

Pin Configuration

Ultrasonic Sensor

Trig Pin → Arduino Pin 8
Echo Pin → Arduino Pin 9
VCC → 5V
GND → GND

LEDs

Green LED → Arduino Pin 5
Yellow LED → Arduino Pin 6
Red LED → Arduino Pin 7

Buzzer

Buzzer Positive → Arduino Pin 4
Buzzer Negative → GND

OLED Display (I2C)

SDA → Arduino A4
SCL → Arduino A5
VCC → 5V
GND → GND

Working Principle

Ultrasonic Distance Calculation

Ultrasonic sensor continoulsy sending the ultrasonic wave from the transmitter and return back to the ultrasonis sensor. there is an echo on the ultrsonic sensor which can detect the ultrasonic wave. so, we can calculate the distnace by usin the time , speed formula. calculation will be must in our project Distance Measurement with Arduino.

The distance is calculated using the formula:

Distance (cm) = (Time × Speed of Sound) ÷ 2

Where the speed of sound in air is approximately 0.034 cm/µs.

OLED Display for Distance Visualization

An OLED display is used instead of an LCD because it offers:

Better contrast
Lower power consumption
No backlight required
Compact size

In this project, the OLED displays the distance value using a large font size, making it easily readable even from a distance. The title is displayed in a smaller font, while the distance value is emphasized.

LED and Buzzer Alert System

The LED and buzzer system provides instant feedback about object proximity:

Green LED indicates a safe distance
Yellow LED acts as a warning indicator
Red LED signals danger
Buzzer produces a continuous beep in danger condition

The buzzer uses the tone() function, which generates a continuous sound until noTone() is called. This ensures a clear and uninterrupted alert when the object is too close.

Distance Measurement with Arduino Code

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Pins
#define trigPin 8
#define echoPin 9

#define greenLED 5
#define yellowLED 6
#define redLED 7
#define buzzer 4

long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  pinMode(greenLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(redLED, OUTPUT);
  pinMode(buzzer, OUTPUT);

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
}

void loop() {
  // Ultrasonic trigger
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  // OLED Display
  display.clearDisplay();

  display.setTextSize(1);   // Small title
  display.setTextColor(WHITE);
  display.setCursor(0, 0);
  display.println("Distance:");

  display.setTextSize(3);   // BIG font for value
  display.setCursor(0, 20);
  display.print(distance);
  display.println(" cm");

  display.display();

  // LED & Buzzer Logic
  if (distance > 16) {
    digitalWrite(greenLED, HIGH);
    digitalWrite(yellowLED, LOW);
    digitalWrite(redLED, LOW);
    noTone(buzzer);   // buzzer OFF
  }
  else if (distance <= 16 && distance > 8) {
    digitalWrite(greenLED, LOW);
    digitalWrite(yellowLED, HIGH);
    digitalWrite(redLED, LOW);
    noTone(buzzer);   // buzzer OFF
  }
  else { // distance <= 15
    digitalWrite(greenLED, LOW);
    digitalWrite(yellowLED, LOW);
    digitalWrite(redLED, HIGH);
    tone(buzzer, 1000); // Continuous beep at 1kHz //Distance Measurement with Arduino
    delay(50);
    noTone(buzzer);
     delay(50);

  }

  delay(200);
}

Now we all need to know how to upload the code into Arduino, which software and whats the method to upload. so, there is a guide to upload the Arduino code.

Arduino Code Explanation

The Arduino code performs the following tasks:

Initializes the OLED display
Sends trigger pulses to the ultrasonic sensor
Reads the echo time and calculates distance
Displays the distance on the OLED screen
Controls LEDs based on distance range
Activates continuous buzzer alert when distance is below threshold

The logic is written in a clean and modular way so that beginners can easily understand and modify it.

Advantages of This Project

Simple and reliable distance measurement
Clear visual output using OLED display
Loud and effective alert system
Low power consumption
Easily expandable

Applications: Distance Measurement with Arduino

This Arduino distance measurement system can be used in many real‑world applications, including:

Obstacle detection systems
Smart parking assistance
Industrial safety alarms
Water level monitoring
Proximity alert devices
Robotics and automation projects
Home security systems

Customization Ideas

You can easily enhance this project by:

Adding different buzzer patterns for different distances
Displaying warning messages on OLED
Using a relay for automatic control
Logging distance data
Adding wireless communication (Bluetooth or Wi‑Fi)

Troubleshooting Tips for Distance Measurement with Arduino

If OLED does not display anything, check the I2C address
Ensure proper power supply connections
Use resistors with LEDs to avoid damage
Adjust distance thresholds according to your needs
Avoid placing ultrasonic sensor near soft surfaces

Conclusion

This Arduino ultrasonic distance measurement project demonstrates how simple components can be combined to create a powerful and practical system. By integrating an OLED display, LED indicators, and a continuous buzzer alert, the project becomes highly effective for safety and monitoring applications.

The clear visual output and audible warning make this project ideal for beginners, students, and hobbyists looking to learn sensor interfacing and real‑time feedback systems. With minor modifications, this project can be adapted for numerous real‑world scenarios.

Whether you are building this as a learning exercise or integrating it into a larger system, this project provides a strong foundation for future Arduino‑based innovations.

Happy Learning and Happy Building! 🚀

Ultrasonic Distance Measurement with Arduino and OLED Display (OLED + LEDs + Buzzer Alert)

Introduction

Why Use an Ultrasonic Sensor for Distance Measurement?