A screen is a major accessory for the boards.
With colour and touch, it provides a powerful and interactive interface to the sketches.
TFT Screens with Touch
Standard screens come with 8- or 16-parallel bus for data and 4 pins for commands, or with SPI or I²C protocols.
Most of the time, the LCD controllers feature basic pixel management. However, some controllers are full GPUs, with elaborate graphic primitives and embedded fonts.
So I started exploring standard screens and released the LCD_screen Library Suite, which is the continuation of the former Serial_LCD, but for screens managed directly.
E-Ink and Reflective Displays
Monochrome LCD provides an easy introduction to displays.
My first display was a 4 lines by 20 characters LCD with I²C connection. It is very easy to interface and doesn't require a large broadband to operate. I'm still using it for my fischertechnik models.
Similar monochrome screens offer a 128 x 64 graphic area.
Most of the times, they operate at 5 V and are being replaced by OLED displays running at 3.3 V.