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ESP32 - Button Count - OLED
In this tutorial, we will explore ESP32 to achieve the following objectives:
- Counting the number of times a button is pressed.
- Displaying the count number on an OLED display.
- Implementing automatic vertical and horizontal center alignment for the count number on the OLED display.
Additionally, the tutorial addresses the debouncing of the button without utilizing the delay() function. For an understanding of why debouncing is essential, refer to the explanation provided in Why do we need debouncing?.
This comprehensive guide will help you integrate button press counting, OLED display functionality, and debouncing techniques seamlessly with your ESP32 project.
Hardware Used In This Tutorial
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 in this section are Amazon affiliate links, meaning we may earn a commission at no additional cost to you if you make a purchase through them. Additionally, some links direct you to products from our own brand, DIYables.
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.
ESP32 Code - displaying button count on OLED
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-button-count-oled
*/
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <ezButton.h>
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // create SSD1306 display object connected to I2C
ezButton button(27); // create ezButton object that attach to the ESP32 pin GPIO27
unsigned long lastCount = 0;
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
button.setDebounceTime(50); // set debounce time to 50 milliseconds
button.setCountMode(COUNT_FALLING);
}
void loop() {
button.loop(); // MUST call the loop() function first
unsigned long count = button.getCount();
if (lastCount != count) {
Serial.println(count); // print count to Serial Monitor
oled.clearDisplay(); // clear display
oled.println(count); // display count
oled.display(); // show on OLED
lastCount != count;
}
}
Quick Instructions
- If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
- Do the wiring as above image.
- Connect the ESP32 board to your PC via a micro USB cable
- Open Arduino IDE on your PC.
- Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
- Click to the Libraries icon on the left bar of the Arduino IDE.
- Search “ezButton”, then find the button library by ArduinoGetStarted
- Click Install button to install ezButton library.
- Search “SSD1306”, then find the SSD1306 library by Adafruit
- Click Install button to install the library.
- You will be asked for intalling some other library dependencies
- Click Install All button to install all library dependencies.
- Copy the above code and open with Arduino IDE
- Click Upload button on Arduino IDE to upload code to ESP32
- Press button several times
- See the counting number changed on OLED
The above code just displays the button press count on the top left corner. Let's modify the code to centralize it!
ESP32 Code - Vertical and Horizontal Center Align on OLED
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-button-count-oled
*/
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <ezButton.h>
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // create SSD1306 display object connected to I2C
ezButton button(27); // create ezButton object that attach to the ESP32 pin GPIO27
unsigned long lastCount = 0;
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
button.setDebounceTime(50); // set debounce time to 50 milliseconds
button.setCountMode(COUNT_FALLING);
}
void loop() {
button.loop(); // MUST call the loop() function first
unsigned long count = button.getCount();
if (lastCount != count) {
Serial.println(count); // print count to Serial Monitor
String text = String(count);
oledDisplayCenter(text);
lastCount != count;
}
}
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();
}
※ NOTE THAT:
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.
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