ESP8266 - Ultrasonic Sensor - OLED
This tutorial instructs you how to acquire the distance from an ultrasonic sensor and display it on an OLED.
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .
Additionally, some of these links are for products from our own brand, DIYables .
Overview of OLED and Ultrasonic Sensor
If you are not familiar with OLED and Ultrasonic Sensor (including pinout, functioning, programming, etc.), the following tutorials can help:
- ESP8266 - OLED tutorial
- ESP8266 - Ultrasonic Sensor tutorial
Wiring Diagram
- If powering ESP8266 via USB port:
This image is created using Fritzing. Click to enlarge image
- If powering ESP8266 via USB port but power is not enough, use an external power source for OLED display and sensor
This image is created using Fritzing. Click to enlarge image
- If powering ESP8266 via Vin pin:
This image is created using Fritzing. Click to enlarge image
See more in ESP8266's pinout and how to supply power to the ESP8266 and other components.
ESP8266 Code - Ultrasonic Sensor - OLED
/*
* This ESP8266 NodeMCU code was developed by newbiely.com
*
* This ESP8266 NodeMCU code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/esp8266/esp8266-ultrasonic-sensor-oled
*/
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define OLED_WIDTH 128 // OLED display width, in pixels
#define OLED_HEIGHT 64 // OLED display height, in pixels
#define TRIG_PIN D5 // The ESP8266 pin connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN D6 // The ESP8266 pin connected to Ultrasonic Sensor's ECHO pin
Adafruit_SSD1306 oled(OLED_WIDTH, OLED_HEIGHT, &Wire, -1); // create SSD1306 display object connected to I2C
String distance_str;
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
distance_str.reserve(10); // to avoid fragmenting memory when using String
}
void loop() {
// Produce a 10-microsecond pulse to the TRIG pin.
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
// Measure the pulse duration from the 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");
distance_str = String(distance_cm, 2); // two decimal places
distance_str += " cm";
Serial.println(distance_str); // print the temperature in Celsius to Serial Monitor
oled_display_center(distance_str); // display temperature on OLED
}
void oled_display_center(String text) {
int16_t x1;
int16_t y1;
uint16_t width;
uint16_t height;
oled.getTextBounds(text, 0, 0, &x1, &y1, &width, &height);
// center the display both horizontally and vertically
oled.clearDisplay(); // clear display
oled.setCursor((OLED_WIDTH - width) / 2, (OLED_HEIGHT - height) / 2);
oled.println(text); // text to display
oled.display();
}
Detailed Instructions
To get started with ESP8266 on Arduino IDE, follow these steps:
- Check out the how to setup environment for ESP8266 on Arduino IDE tutorial if this is your first time using ESP8266.
- Wire the components as shown in the diagram.
- Connect the ESP8266 board to your computer using a USB cable.
- Open Arduino IDE on your computer.
- Choose the correct ESP8266 board, such as (e.g. NodeMCU 1.0 (ESP-12E Module)), and its respective COM port.
- Click to the Libraries icon on the left bar of the Arduino IDE.
- Search for “SSD1306” and locate the SSD1306 library by Adafruit.
- Then, press the Install button to install the library.
- You will be prompted to install additional library dependencies.
- To install all of them, click the Install All button.
- Copy the code and open it in the Arduino IDE.
- Click the Upload button in the IDE to transfer the code to the ESP8266.
- Move your hand in front of the sensor.
- Check out the outcome on the OLED display and in the Serial Monitor.
※ NOTE THAT:
The code below will enable automatic horizontal and vertical centering of text on an OLED display. To learn more, please see How to vertical/horizontal center on OLED.