After Qualcomm’s purchase of Arduino it has left many wondering what market its new Uno Q board is trying to target. Taking the ongoing RAM-pocalypse as inspiration, [Bringus Studios] made a tongue-in ...

A standard telephone keypad, with four rows of three keys each. The top row consists of 1, 2, and 3, with keys continuing down in order until the last row, which is usually *, 0, and #. Such a keypad ...

The PCB must be mounted floated, otherwise key presses don't work reliable. Connect pins 3 and 4 on connector P1 for 16-pin button mode. Smaller keypads with less pins may work, but are not tested.