[exemplo] I2C OLED

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// OLED display TWI address
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

int dummyVal = 0;

void setup() {
  // inicializa ecrã
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  display.clearDisplay();
  display.display();

  // imprime linha de texto
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(55, 30);
  display.print(F("..."));

  // actualiza ecrã
  display.display();
}

void loop() {
  display.clearDisplay();
  display.display();

  display.setTextSize(3);
  display.setTextColor(WHITE);
  display.setCursor(60, 25);

  if (dummyVal == 0) {
    display.print(F("\\"));
  }
  else if (dummyVal == 1) {
    display.print(F("|"));
  }
  else if (dummyVal == 2) {
    display.print(F("/"));
  }
  else if (dummyVal == 3) {
    display.print(F("-"));
  }

  if (dummyVal >= 3) {
    dummyVal = 0;
  }
  else {
    dummyVal = dummyVal + 1;
  }

  display.display();
}