You can read the state of a button using Arduino and a few lines of code. The actual state is shown in the Serial Monitor window as 0 or 1, 0 meaning the button is not pressed and 1 that the button is ...
If you want to build a button array, follow this diagram. The main idea here is to connect each button to a diode in a row by column fashion, and read all the rows column by column. Rows works as ...