OLED Hello World
Render real text through Adafruit GFX into the SSD1306 framebuffer.
Wire it up
Disconnect power before changing connections. Follow terminal names rather than wire colors.
| From | To | Why it matters |
|---|---|---|
| SSD1306 OLED (oled1) · VCC | Uno · 3.3V | Power connection |
| SSD1306 OLED (oled1) · GND | Uno · GND.1 | Ground reference |
| SSD1306 OLED (oled1) · SDA | Uno · A4 | Match this terminal to the sketch |
| SSD1306 OLED (oled1) · SCL | Uno · A5 | Match this terminal to the sketch |
The complete sketch
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
Adafruit_SSD1306 display(128, 64, &Wire, -1);
void startDisplay() {
if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) while (true) {}
display.clearDisplay(); display.setTextSize(1); display.setTextColor(SSD1306_WHITE);
}
void setup() {
startDisplay(); display.setCursor(0, 8);
display.println("Hello Circuitera");
display.println("128 x 64 OLED"); display.display();
}
void loop() {}
The launch buttons use this same code and a matching saved circuit.
Build it step by step
Open a complete project
Launch in Simulator creates a separate Uno sketch and its matching wired circuit. Existing sketches are preserved. Press Run to compile and execute.
Explore the live circuit
Change the text and rerun. Keep text inside the 128×64 screen.
Try it on hardware
Disconnect power while wiring. Match terminal names in the table, select the exact board, Verify, then connect and upload. Check component ratings and power requirements first.
Understand the sketch
Buffer then send
Drawing changes a RAM buffer. display.display sends that buffer over I2C to address 0x3C; without it the screen will not update.
If something is different
No image
Use the supported SSD1306 I2C display, address 60 decimal (0x3C), and the A4/A5 bus. This is not an SH1106 driver.
Expected output and tested scope
The SSD1306 framebuffer contains the text rendered through Adafruit GFX.
Version 1 · Last source- and build-matched test: 2026-10-25. Actual shipped AVR-GCC WASM compilation and Uno AVR engine execution; no physical hardware test.
Supported tutorial target: Arduino Uno R3 / ATmega328P. Compile: PASS · Modeled execution: PASS. Other boards require a separate review of pins, voltage, libraries and the exact build profile.