Keypad 4 X 3 Membrane
Punch in your secret key into this numeric matrix keypad. This keypad has 12 buttons, arranged in a telephone-line 3x4 grid. It's made of a thin, flexible membrane material with an adhesive backing (just remove the paper) so you can attach it to nearly anything. The keys are connected into a matrix, so you only need 7 microcontroller pins (3-columns and 4-rows) to scan through the pad. Check the tutorials for links to an Arduino library and example code.
Weight: 7.5 grams
Keypad dimensions: 70mm x 77mm x 1mm (2.75" x 3" x 0.035")
Length of cable + connector: 85mm
7-pin 0.1" pitch connector