Next is a project example, where the Arduino is instructed to do something based on a correct key (secret number) being entered into the keypad, probably the most demanded application of the keypad.

If you want to add a keypad to your Arduino project, the options are pretty limited. There’s that red and blue 4×4 membrane we’ve all seen in password-protected door lock projects, and the ...

[Ronnie] built a laser trip wire complete with an LCD screen and keypad for arming and disarming the system. The brains of the project is an Arduino.