The Keypad library allows your uno to read a matrix type keypad. 4×4 numeric keypads are most widely used in numerous mini project which requires the user or the operator to give command to the system or to feed in some data.

Keyboard for the pin interface.4X4 design, 10 numeric keys, 4 English keys,2 function keys. There is a switch connecting each row and column. So the combinations of rows and columns makes up the 16 inputs.

Circuit board is PCB double-panel