If you are tired of those old 4 x 4 keypads which use up most of your digital I/O's then this is a great product for you. The Nintendo DS Touch Screen uses only 4 analog inputs, and allows you to be creative with your keypads.
This was originally intended for use on top of a LCD display inside a Nintendo DS. By placing a printed keypad under the screen, you get a user defined keypad!
Check out this awesome tutorial using an Arduino.
Recommended with this product: Touch Screen Connector
Dimensions: 2.2 x 2.75"