ESP32 - Ultrasonic Sensor - OLED

This tutorial instructs you how to use ESP32 to read the distance from ultrasonic sensor and display it on an OLED.

ESP32 Ultrasonic Sensor OLED

Hardware Used In This Tutorial

1×ESP-WROOM-32 Dev Module
1×USB Cable Type-C
1×SSD1306 I2C OLED Display 128x64
1×Ultrasonic Sensor
1×Jumper Wires
1×(Optional) DC Power Jack
1×(Recommended) ESP32 Screw Terminal Adapter

Or you can buy the following sensor kits:

1×DIYables Sensor Kit (30 sensors/displays)
1×DIYables Sensor Kit (18 sensors/displays)
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Introduction to OLED and Ultrasonic Sensor

We have specific tutorials about OLED and Ultrasonic Sensor. Each tutorial contains detailed information and step-by-step instructions about hardware pinout, working principle, wiring connection to ESP32, ESP32 code... Learn more about them at the following links:

Wiring Diagram

  • The wiring diagram with power supply from USB cable
ESP32 Ultrasonic sensor OLED wiring diagram

This image is created using Fritzing. Click to enlarge image

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.

  • The wiring diagram with power supply from 5v adapter
ESP32 Ultrasonic sensor OLED 5V power wiring diagram

This image is created using Fritzing. Click to enlarge image

ESP32 Code - Ultrasonic Sensor - OLED

/* * This ESP32 code is created by * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit */ #include <Wire.h> #include <Adafruit_GFX.h> #include <Adafruit_SSD1306.h> #define SCREEN_WIDTH 128 // OLED display width, in pixels #define SCREEN_HEIGHT 64 // OLED display height, in pixels #define TRIG_PIN 14 // ESP32 pin GPIO14 connected to Ultrasonic Sensor's TRIG pin #define ECHO_PIN 27 // ESP32 pin GPIO27 connected to Ultrasonic Sensor's ECHO pin Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // create SSD1306 display object connected to I2C String tempString; void setup() { Serial.begin(9600); // initialize OLED display with address 0x3C for 128x64 if (!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { Serial.println(F("SSD1306 allocation failed")); while (true); } delay(2000); // wait for initializing oled.clearDisplay(); // clear display oled.setTextSize(2); // text size oled.setTextColor(WHITE); // text color oled.setCursor(0, 10); // position to display tempString.reserve(10); // to avoid fragmenting memory when using String } void loop() { // generate 10-microsecond pulse to TRIG pin digitalWrite(TRIG_PIN, HIGH); delayMicroseconds(10); digitalWrite(TRIG_PIN, LOW); // measure duration of pulse from ECHO pin long duration_us = pulseIn(ECHO_PIN, HIGH); // calculate the distance float distance_cm = 0.017 * duration_us; // print the value to Serial Monitor Serial.print("distance: "); Serial.print(distance_cm); Serial.println(" cm"); tempString = String(distance_cm, 2); // two decimal places tempString += " cm"; Serial.println(tempString); // print the temperature in Celsius to Serial Monitor oledDisplayCenter(tempString); // display temperature on OLED } void oledDisplayCenter(String text) { int16_t x1; int16_t y1; uint16_t width; uint16_t height; oled.getTextBounds(text, 0, 0, &x1, &y1, &width, &height); // display on horizontal and vertical center oled.clearDisplay(); // clear display oled.setCursor((SCREEN_WIDTH - width) / 2, (SCREEN_HEIGHT - height) / 2); oled.println(text); // text to display oled.display(); }

Quick Instructions

  • Open Arduino IDE.
  • Click to the Libraries icon on the left bar of the Arduino IDE.
  • Search “SSD1306”, then find the SSD1306 library by Adafruit
  • Click Install button to install the library.
ESP32 OLED library
  • You will be asked for intalling some other library dependencies
  • Click Install All button to install all library dependencies.
ESP32 Adafruit GFX sensor library
  • Copy the above code and paste it to Arduino IDE
  • Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
  • Move your hand in front of sensor
  • See the result on OLED and Serial Monitor


The about code automatically horizontal and vertical center aligns the text on OLED display. See How to vertical/horizontal center on OLED for more detail.

Video Tutorial

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