For this, just wire up the hardware (arduino+keypad) as described earlier ... Note that the good old 3×4 telephone keypad from your junk box can also be used for this project. Like most keypads, it is ...

He used an Arduino, and multiplexed RGB LEDs with some digital potentiometers to create a color mixing keypad. Since we couldn’t fit the complete 4×4 keypad into a standard 2 gang wall box ...

Figuring an ‘electronic box that plays sounds’ wouldn’t ... The code is very easy with the Arduino keypad library, and should stand up to the rigors of being handled by a child.

You can also make one for yourself. Instructables user MakersBox did just that, with a tiny, modular Arduino-compatible board that can fit inside a Tic Tac box. The build uses a handful of parts ...

or a keypad. Your smartphone can display information, or playback sound. Why not let the smartphone be the shield? Enter 1Sheeld. 1Sheeld connects your Arduino to your smartphone (Android only ...