Using multiple buttons on a single pin is possible. There are modules for that. Also there is a great library called AceButton to make the button click easily readable. The library needs you to set...
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications.