02 - Board Hardware

A push button is a switch which makes a momentary connection when pressed.  The four push buttons used in the this board are connected to Digital Input pins.  The Internal Pullup resistor prevents the

input from floating then not pressed and giving erroneous readings.   This internal resistance is attached using the INPUT_PULLUP setting in the pinMode statement.

Thus, when reading the pushbutton, an un-pressed pushbutton will read as 1 (pulled HIGH) and a pressed button will read as 0 (shorted to Ground).