A 4x4 matrix 16-key button keypad is a type of input device that consists of a grid of 16 buttons or keys arranged in a 4x4 matrix. It is commonly used as a compact and convenient way to input data or control a device.

To use a 4x4 matrix keypad, each button or key is assigned a unique combination of row and column coordinates. When a button is pressed, it closes a circuit between the corresponding row and column wires, allowing the keypad to determine which button was pressed. The keypad can then send this information to a microcontroller or other device for processing.

4x4 matrix keypads are often used in applications where a larger number of buttons or keys are needed, but space is limited. They are commonly found in devices such as alarm systems, security access panels, and handheld electronic devices.

This 4x4 matrix of tactile switches are perfect for adding a user-interface to your system at the lowest possible cost. Perfect for Arduino projects.

There are 16 buttons in total and has 8 pins in total for usage.