We like this approach because instead of doing some hard-core LCD ... Arduino, your add-ons are probably meant for a 5V power rail and logic levels. The RPi outputs 3.3V logic. You could use ...

[Usmar A. Padow] put together an Arduino Uno, SD card, four line character LCD, and PS/2 keyboard. but he’s also included alternative options to go without an LCD screen by using a computer ...