When building Arduino projects for beginners, you'll usually need both input and output sensors. However, you can come across some simple projects like the Blink example that only require an LED ...

There is a boring part of every computer introduction class that shows how a computer is made up of input, output ... that’s trivial to interface to an Arduino or other small microcontroller.

For example, if you use a particular brand ... in Arduino function that sets how a given I/O pin on the Arduino behaves - either input or output. In this case, we're telling the Arduino to use ...

In the Leonardo, an op-amp between the ATmega pin and the led means that loading is minimal and the pin can easily be used as an Arduino input. This buffer is missing on the Micro, which means even ...