Arduino的顯示方式最常見的是用1602 LCD，第二順位應該就是OLED了。OLED的優點在於顯示效果非常漂亮，還能顯示圖片，尺寸雖然不大，但完全不影響閱讀效果，所以相當受開發者的喜愛。
市面上OLED常見的有0.96吋、0.91吋，還有1.3吋。0.96和0.91吋都屬於SSD1306晶片規格，可用相同的函式庫，1.3吋是SH1106，傑森會再寫另一篇來介紹。
OLED接線很簡單，它是用I2C介面，所以只有4條線，SDA、SCL接到Arduino Uno板上的A4、A5，VCC接到3.3V，GND接GND，就搞定了。
再來就是安裝函式庫了，這裡傑森選的是Adafruit提供的函式庫，大家也可以選擇u8glib，但傑森發現u8glib對於圖形文字檔要求比較嚴格，所以現在都改用Adafruit SSD1306函式庫；而這個函式庫還要Adafruit GFX Library函式庫來配合，所以請一併安裝。
再來就要寫程式囉！基本上0.96吋和0.91吋的程式都相同，只有在設定尺寸和座標時有差別。
- 0.96吋：128x64
- 0.91吋：128x32
因為我們要在畫面中顯示圖形，所以要先把圖形轉成文字陣列，傑森認為Image2LCD這套最好用，大家可以試試。
Image2LCD下載網址：
http://www.e-paper-display.com/download_detail/downloadsId=625.html
先在繪圖軟體中畫好圖，存成JPG格式，在Image2LCD打開，基本上只有「輸出灰度」改成「單色」，寬度和高度設成128、64，然後就可以進行「保存」了。然後把得到的陣列COPY到我們的程式中即可。
我們先以0.96吋為例，傑森簡化了範例程式ssd1306_128x64_i2c，只留下顯示文字和顯示圖形。
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128 // OLED 寬度像素
#define SCREEN_HEIGHT 64 // OLED 高度像素
// 設定OLED
#define OLED_RESET 4 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
//自訂圖形，從Image2LCD轉過來的，尺寸是128x48，少掉的16個像素是上方黃色區塊(假設是用藍黃雙色的OLED)
//本範例為了在上方區塊顯示文字，所以圖形就沒有涵蓋整個高度
static const unsigned char PROGMEM logo_bmp[] =
{
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void setup() {
Serial.begin(9600);
// 偵測是否安裝好OLED了
if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // 一般1306 OLED的位址都是0x3C
Serial.println(F("SSD1306 allocation failed"));
for(;;); // Don't proceed, loop forever
}
// 顯示Adafruit的LOGO，算是開機畫面
display.display();
delay(1000); // 停1秒
// 清除畫面
display.clearDisplay();
testdrawstyles(); // 測試文字
testdrawbitmap(); // 顯示圖形
}
void loop() {
}
void testdrawstyles(void) {
display.clearDisplay();
display.setTextSize(2); // 設定文字大小
display.setTextColor(1); // 1:OLED預設的顏色(這個會依該OLED的顏色來決定)
display.setCursor(0,0); // 設定起始座標
display.print("Hello OLED"); // 要顯示的字串
display.display(); // 要有這行才會把文字顯示出來
delay(1000);
}
void testdrawbitmap(void) {
//display.clearDisplay();
//顯示圖形，x,y,圖形文字,寬,高,1:OLED預設的顏色(這個會依該OLED的顏色來決定)
display.drawBitmap(0,16,logo_bmp, 128, 48, 1);
display.display(); // 要有這行才會把文字顯示出來
delay(1000);
}
程式中傑森都有簡單做了註解，感該不難懂的。
如果要用的是0.91吋的OLED，#define SCREEN_HEIGHT 64 這行改成#define SCREEN_HEIGHT 32，就可以了。當然圖形尺寸要注意一下就是了。
0.96吋OLED範例程式下載：
http://jmaker.banner.tw/doc/ssd1306_128x64_i2c.zip
0.91吋OLED範例程式下載：
http://jmaker.banner.tw/doc/ssd1306_128x32_i2c.zip