The OONTZ uses a 3D printed case, a 16 button keypad, an Arduino Leonardo, a monochrome driver, and a few potentiometers. It's actually a pretty simple thing to build yourself provided you can the ...

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 [Lauri] has posted an example of just such a program on his GitHub repository for an Arduino. Heavy analog electronics, for sure, but something to keep in mind if you’re reading more than 12 ...