ESP8266 - Button Count - OLED
This tutorial instructs you how to use ESP8266 and button to count the press events and then display the value on OLED. In detail:
- The ESP8266 counts how many times a button is pressed
- The ESP8266 displays the count number on an OLED.
- The ESP8266 automatically aligns the count number to the center of the OLED display, both horizontally and vertically.
In this tutorial, we will be debouncing a button without using the delay() function. For more information on why debouncing is necessary, please see Why do we need debouncing?
You can adapt this to work with different sensors instead of the button.
Hardware Preparation
Or you can buy the following sensor kit:
| 1 | × | DIYables Sensor Kit 30 types, 69 units |
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Wiring Diagram
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 - displaying button count on 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-button-count-oled
*/
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <ezButton.h>
#define OLED_WIDTH 128 // OLED display width, in pixels
#define OLED_HEIGHT 64 // OLED display height, in pixels
Adafruit_SSD1306 oled(OLED_WIDTH, OLED_HEIGHT, &Wire, -1); // create SSD1306 display object connected to I2C
ezButton button(7); // create ezButton object for pin 7;
unsigned long prev_count = 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 (prev_count != count) {
Serial.println(count); // print count to Serial Monitor
oled.clearDisplay(); // clear display
oled.println(count); // display count
oled.display(); // show on OLED
prev_count != count;
}
}
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 “ezButton”, then locate the button library provided by ArduinoGetStarted.
- Press the Install button to install ezButton library.
- Search for “SSD1306” and locate the SSD1306 library created by Adafruit.
- Click the Install button to add 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 with the Arduino IDE.
- Hit the Upload button on the Arduino IDE to compile and upload the code to the ESP8266.
- Press the button multiple times.
- Check out the changing count number on the OLED.
The code above shows the number of button presses in the top left corner. Let's make a change to center it!
ESP8266 Code - Vertical and Horizontal Center Align on 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-button-count-oled
*/
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <ezButton.h>
#define OLED_WIDTH 128 // OLED display width, in pixels
#define OLED_HEIGHT 64 // OLED display height, in pixels
Adafruit_SSD1306 oled(OLED_WIDTH, OLED_HEIGHT, &Wire, -1); // create SSD1306 display object connected to I2C
ezButton button(7); // create ezButton object for pin 7;
unsigned long prev_count = 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 (prev_count != count) {
Serial.println(count); // print count to Serial Monitor
String text = String(count);
oled_display_center(text);
prev_count != count;
}
}
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();
}
※ NOTE THAT:
This code will horizontally and vertically center the text on an OLED display. For more information, please refer to How to vertical/horizontal center on OLED.