Whether your project is space constrained or you just want a cool look and a high tech keypad, the 4x4 membrane keypad is the ideal choice for your project.

The board is self adhesive, and you can attach it to almost any surface by peeling the sticker from its back and sticking into the desired location.

The button states can be detected by reading the combination of four rows and four columns provided by the matrix keypad. Underneath each key, there is an ultrathin pushbutton connected with one end to a row, and the other end to a column, as shown below:

Fig. 1 Membrane Keypad Connections