Build your Ultrasonic Distance Meter!

An ultrasonic distance meter is a simple and effective project for anyone interested in learning about sensors and measurement. It uses sound waves to detect how far an object is and displays that value, making it useful for obstacle detection, parking sensors, or general distance measuring.

Components

What you need:

Microcontroller (Arduino Uno or Nano recommended)
Ultrasonic Sensor (HC-SR04)
OLED Display (optional, SSD1306 preferred)
Jumper Wires
Breadboard
USB Cable
Access to a 3D printer (very optional)

Steps to follow when making your first Ultrasonic Distance Meter

Design your circuit on paper
- Draw a circuit diagram that includes the ultrasonic sensor and OLED display. Decide whether the project will be powered by USB or battery. Think about how and where the distance will be displayed.
Connect the HC-SR04 sensor to the Arduino
- VCC → 5V
- GND → GND
- TRIG → Digital pin (e.g. D9)
- ECHO → Digital pin (e.g. D10)
Connect the OLED display to the Arduino
- This step is optional. You may decide to use Serial.println to output the distance instead.
- Use I2C:
  - VCC → 3.3V or 5V
  - GND → GND
  - SDA → A4 (on Uno)
  - SCL → A5 (on Uno)
Write code to measure and display the distance
- Use ChatGPT to help you write Arduino code that:
  - Sends a pulse from the TRIG pin
  - Measures the pulse duration received on the ECHO pin
  - Converts the time into distance in cm
  - Displays the result on the OLED screen or in the console

Guidelines / Tips to making your Ultrasonic Distance Meter

Measure accurately
- The HC-SR04 works best between 2 cm and 400 cm. Avoid using it with absorbent or soft surfaces like fabric or foam which can affect accuracy.
Use an OLED for better readability
- An SSD1306 OLED display is ideal for displaying the distance. It uses I2C, so it only requires two wires and gives a crisp output, even in bright light.
Use a 3D printed case
- You can design and 3D print a case that houses your Arduino, sensor, and OLED. This protects your circuit and gives your project a more professional look. This is completely optional.
Add a buzzer for feedback
- You can connect a buzzer to sound an alert when an object is closer than a set distance (e.g., 10 cm). This turns your project into a parking sensor or obstacle warning system.

How to develop your project

Add a proximity alarm
- Connect an LED and buzzer to alert you when an object is within a certain range. This adds functionality and introduces basic conditional logic in code.
Add multiple sensors
- Use digital pins to switch between multiple ultrasonic sensors and monitor different directions. This is useful for robots and automation systems.