A keypad is one of the most commonly used input devices in microprocessor applications. In a standard keypad wired as an X-Y switch matrix, normally-open switches connect a row to a column when ...

Arduinos are a godsend for the DIY/Tinkerer community, but there’s all sorts of stuff they just can’t do out of the box. Sure, you can add tons of functionality via strap-on boards called “shields”..