it’s great for a quick-and-dirty circuit diagrams. Not exactly schematics, but [Duckman] has some Arduino pinout diagrams he made using ASCII-art. These could be useful when pasted into source ...

Luckily, requisite googling found a “multifunction shield” for the Arduino Uno platform available at a low cost from most internet suppliers. Here is a circuit diagram of the multifunction ... for ...

functional block diagrams, and other programming systems covered under the IEC 61131-3 standard. Not only that, it allows the combination of these types of PLC programming with Arduino sketches.