Arduino Code and Video for HC-SR04 Ultrasonic Distance Sensor with SSD1306 OLED Display

Arduino Code and Video for HC-SR04 Ultrasonic Distance Sensor with SSD1306 OLED Display

In this tutorial, we will demonstrate how to use the HC-SR04 ultrasonic distance sensor in conjunction with the SSD1306 OLED display to visualize distance measurements. This project allows you to measure distances without needing a computer, making it ideal for various applications, including robotics. By the end of this project, you will have a functional setup that displays distance readings directly on the OLED screen.

As we proceed, I will explain the wiring connections required for both components and provide a walk-through of the Arduino code that integrates these components. This will help you understand how the sensor measures distance and how to output that data to the OLED display. For further clarification, you can refer to the video associated with this tutorial (in video at 00:00).

Hardware Explained

The main components of this project are the HC-SR04 ultrasonic distance sensor and the SSD1306 OLED display. The HC-SR04 operates using ultrasonic sound waves; it emits a sound pulse via the trigger pin and listens for the echo on the echo pin. By calculating the time taken for the sound to return, it can determine the distance to an object. This sensor is very effective for short-range measurements, typically up to 400-500 cm.

The SSD1306 OLED display is an I2C interface display that allows you to display text and graphics. It communicates via two pins: SDA (data line) and SCL (clock line). In our setup, these pins connect to specific Arduino pins, allowing for easy integration and control.

Datasheet Details

Manufacturer	Various
Part number	HC-SR04
Logic/IO voltage	5 V
Supply voltage	5 V
Output current (per channel)	15 mA
Peak current (per channel)	20 mA
PWM frequency guidance	N/A
Input logic thresholds	0.3Vcc to 0.7Vcc
Voltage drop / R_DS(on) / saturation	N/A
Thermal limits	0-70 °C
Package	4-pin module
Notes / variants	Standard module

Ensure proper power supply (5 V) for both components.
Use pull-up resistors if necessary for I2C communication.
Keep trigger and echo lines short to avoid interference.
Check the orientation of the ultrasonic sensor for accurate readings.
Use a stable surface for the display to avoid mechanical vibrations.

Wiring Instructions

Arduino wiring for HC-SR04 ultrasonic SSD1306 128x64 OLED

To connect the HC-SR04 ultrasonic sensor, start by wiring the VCC pin (usually red) to the 5V pin on the Arduino. Next, connect the GND pin (typically black or yellow) to one of the Arduino's GND pins. The trigger pin (often blue) should be wired to digital pin 12 on the Arduino, while the echo pin (usually green) should be connected to digital pin 11.

For the SSD1306 OLED display, connect the VCC pin to the 5V pin on the Arduino and the GND pin to GND. The SCL pin should be connected to pin A5 and the SDA pin to pin A4 on the Arduino. If you are using a different Arduino model that has dedicated I2C pins, connect the display directly to those pins instead.

Code Examples & Walkthrough

In the setup function, we initialize the display and the serial communication. The following excerpt demonstrates how the display is set up:

void setup() {
   Serial.begin(9600);// set serial monitor with 9600 baud
   display.begin(SSD1306_SWITCHCAPVCC, 0x3C);  // initialize with the I2C addr 0x3D
}

Here, the display is initialized with the I2C address, allowing it to communicate with the Arduino. The serial monitor is also set up to print distance values.

In the main loop, we clear the display, measure the distance, and print it. The following code snippet shows how we handle the distance measurement:

void loop() {
   display.clearDisplay();
   String distance  = String(sonar.ping_cm());// get distance and convert it to string for display
   robojaxText(distance +"cm", 3, 20, 3, false);
   display.display();
   delay(50); // Wait 50ms between pings
}

This loop continuously measures the distance and updates the display with the current reading. The `robojaxText` function is used to display the text on the OLED screen.

Demonstration / What to Expect

When the setup is complete and the code is uploaded, you should see the distance displayed on the OLED screen in centimeters. As you move an object closer or farther from the sensor, the displayed value should change accordingly. Ensure that the sensor is oriented correctly and is not obstructed (in video at 02:30).