The adhesive backing on this low-profile membrane keypad allows you to place it just about anywhere. The 12 keys are wired in a 4x3 matrix, readily decoded with an Arduino. The electrical connection is via a flat flexible ribbon cable terminated with a breadboard friendly 0.1" pitch single row female connector.
The simplest decoding method requires a digital output for each column and a digital input for each row. The pin count can be reduced by adding a resistor divider network and creatively using the Arduino's analog input capability.
The 0.1" single row female header is breadboard friendly (when coupled with a male single row header). The overall dimensions of the membrane are 78mm Tall x 70mm Wide, The flexible ribbon cable is 75mm long (not including the connector).
This is a great way to experiment with matrix decoding on the Arduino!
QTY: 1 x 12-Button Numeric Membrane Keypad Matrix