Adafruit 4x4 Matrix Keypad [ADA3844]
Punch in your secret key (or Jenny's number ) into this numeric matrix keypad. This keypad has 16 buttons, arranged in a telephone-line 4x4 grid. The keys are connected into a matrix, so you only need 8 microcontroller pins (4-columns and 4-rows) to scan through the pad. Check the tutorials tab for links to an Arduino library and example code.
We include some header so you can plug this into a breadboard with ease, some light soldering is required to attach it. Or you can use plain wires if you like.
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 . Starting from the left there are four row pins, and then to the right are the four column pins.
If you dig our demo, check out the Adafruit FeatherWing OLED - 128x32 OLED
We also have a 3x4 version of this matrix keypad