Each of the 14 digital pins on the Arduino Uno can be used as an input or output, using pinMode(), digitalWrite(), and digitalRead() functions. They operate at 5 volts. Each pin can provide or receive ...

[Gonzho] has been busy the last few years working on his own Arduino Powered Open Source heat pump controller, and the project logs show some nice details of what it takes to start experimenting ...

Then, chances are you already know what an Arduino is, or at the very least ... you might think it comes with a lot more pins. However, their pinouts are surprisingly similar in most aspects.