Tactile Keypad 4x4
A tactile switch is a small device that closes a circuit when pressed. The switch is momentary, which turns ON when pressed and turns OFF when released.
This module is composed of 16 tactile switches set in an arrangement that would look like a keypad. It works by having 4 pins connected to each row and 4 pins for each column. When a button activates, the state of the row pins, as well as the column pins, are changed. Therefore, locating what pin is active.