I quickly created a simple but compact digital tachometer using an Arduino Uno microcontroller and a pretty nice Arduino LCD Keypad Shield. The setup can measure how many times a switch/sensor action ...

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”..