Adafruit 3x4 Phone-style Matrix Keypad
Hey, Jenny, I've got your number! And I'm going to dial 867-5309 into this very nice phone-style matrix keypad. 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.
There's a great Matrix Keypad Arduino library that should work great with this item with minor adjustments. It's basically a sturdier version of our Membrane 3x4 Matrix Keypad and comes with 7 or 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. If yours has an 8th pin, its not used and you can just leave it disconnected