4×4 Keypad Shield

A sixteen-key matrix keypad on a shield, for projects that need numeric entry: door locks, calculators, menu systems and access control. The matrix arrangement reads all sixteen keys using eight pins, and the Keypad library handles the scanning for you in a few lines of code. Pairs naturally with an LCD to build a complete user interface. Sixteen keys using only eight I/O pins; Works with the standard Arduino Keypad library; Ideal for PIN entry and menu navigation; Stacks directly onto an Uno