The Keypad library allows development board to read a matrix type keypad. 4×4 numeric keypads are widely used in project which requires the user to give command to the system or to feed in some data.
You don't need the outer two pins on the left and right for wiring. It's the inner 8 pins that matter.
If you solder on a header, we highly recommend laying down some flux on the pads first, inserting the header pins, then soldering
The standard Keypad library for arduino works out of the box with this particular device.
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