Small OLED displays are one of the most popular choices for modern embedded systems. They offer high contrast, low power consumption and compact size, making them ideal for Arduino, ESP32 and CANABLOX projects.
This article explains how OLED displays work and compares the most common controller chips: SSD1306, SH1106 and SSD1309.
What Is an OLED Display?
OLED stands for Organic Light Emitting Diode. Each pixel generates its own light, which means no backlight is required.
This results in:
- Very high contrast
- Deep black levels
- Wide viewing angles
- Good readability in dark environments
OLED displays are typically monochrome in small modules used for embedded systems.
Common OLED Resolutions
Most small OLED modules use one of the following resolutions:
- 128x32 pixels
- 128x64 pixels
These resolutions are sufficient for:
- Status information
- Menus
- Simple graphics
- Small icons
SSD1306 OLED Displays
The SSD1306 is the most widely used OLED controller.
Typical features:
- Supports I2C and SPI
- Common resolutions: 128x32 and 128x64
- Very strong library support
- Used in many low-cost modules
Advantages of SSD1306
- Excellent compatibility with Arduino libraries
- Large number of example projects
- Easy to integrate
Limitations of SSD1306
- Limited resolution
- Monochrome only
SH1106 OLED Displays
The SH1106 is similar to SSD1306 but has some internal differences.
Typical features:
- Usually I2C interface
- 128x64 resolution
- Slightly different memory layout
Advantages of SH1106
- Often used in larger OLED modules
- Good availability
Limitations of SH1106
- Not fully compatible with SSD1306 libraries
- May require different initialization code
Even though the resolution is the same, software must handle SH1106 differently.
SSD1309 OLED Displays
The SSD1309 is a more advanced controller used in some higher-quality OLED modules.
Typical features:
- Supports SPI and sometimes I2C
- 128x64 resolution
- Improved performance compared with SSD1306
Advantages of SSD1309
- Faster communication in SPI mode
- Better suited for more dynamic content
Limitations of SSD1309
- Less common than SSD1306
- Library support may vary
SSD1306 vs SH1106 vs SSD1309
| Feature | SSD1306 | SH1106 | SSD1309 |
|---|---|---|---|
| Resolution | 128x32 / 128x64 | 128x64 | 128x64 |
| Interface | I2C / SPI | I2C (mostly) | SPI / I2C |
| Library support | Excellent | Good (but different) | Moderate |
| Performance | Good | Good | Better in SPI mode |
| Typical use | General-purpose OLED | Alternative OLED modules | Faster SPI applications |
I2C vs SPI on OLED Displays
Many OLED modules support both I2C and SPI.
- I2C uses fewer wires and is easier to connect
- SPI is faster and better for frequent updates
For simple status displays, I2C is usually sufficient. For animations or fast updates, SPI is preferred.
Power Consumption
OLED displays consume power based on how many pixels are lit.
- Black pixels use almost no power
- White or bright pixels increase consumption
- No backlight means lower idle power than LCD
This makes OLED displays well suited for battery-powered projects.
Typical Use Cases
- Sensor displays
- Status panels
- Small menus
- Portable devices
- Compact embedded systems
OLED displays are especially useful where space is limited and readability is important.
Important Practical Notes
- Most modules use 3.3V logic
- Some boards tolerate 5V, but verify before use
- Always check the controller chip before selecting a library
- SH1106 is not fully compatible with SSD1306 code
- I2C addresses may vary between modules
Conclusion
OLED displays based on SSD1306, SH1106 and SSD1309 are excellent choices for compact, high-contrast displays in embedded systems. SSD1306 is the most widely supported option, SH1106 offers similar functionality with slight differences, and SSD1309 provides improved performance in some applications.
Choosing the right controller and interface ensures reliable operation and easier integration into your project.