We can display a digital clock using an OLED graphic display module. OLED stands for organic light-emitting diode. The OLED display is made up of organic compounds that light up when fed electricity. If you have any experience with LED backlighting and LCD display, an OLED display can be controlled pixel by pixel. This sort of control just isn't possible with an LED and LCD.

There are many models of OLED graphic display. You can review them at https://www.adafruit.com/categories/98. In this section, we will learn to build a digital clock using a Monochrome 0.96" 128 x 64 OLED graphic display. You can buy it on https://www.adafruit.com/products/326 and you can also get it on eBay at low cost. To access an OLED module, we use an I2C protocol on Raspberry Pi:

The I2C OLED graphic display has the following pinouts: GND, 3V3, SCL, and SDA. These pinouts match with your Raspberry Pi I2C.

The I2C (Inter-IC) bus is a bidirectional two-wire serial bus that provides...