Keypad 4x4 Matrix Module Plastic Keys for Arduino
If you are looking for a keypad that has a sleek presentation, but also mimics the functions of a typical keypad membrane, then this 4x4 keypad matrix is that one that suits your taste.
This keypad has 16 different buttons arranged in an array to depict what a keypad looks like. 8 digital pins to control it; 0-9 # * A-D. There is no external power supply needed for this module to operate.
It works by having 4 pins connected to each row and 4 pins for each column. A pressed button changes the state of the row pin and column pins. Therefore, locating what pin activates.
It integrates into your Arduino or even Raspberry Pi projects for having user inputs.