This keypad has 12 buttons, arranged in a telephone-line 3x4 grid. It's made of plastic with sturdy plastic buttons. The keys are connected to a matrix so you only need 7 microcontroller pins (3-columns and 4-rows) to scan through the pad.
Comes with 8 header pins pre-soldered on for easy plugging. Starting from the left there are three column pins, and then to the right are the four row pins. The 8th pin is not used and you can just leave it disconnected
Check out our detailed guide with wiring diagrams, libraries and example sketches for all sorts of matrix keypads.
