Just follow the schematic diagram to complete the construction, and use any standard 9VDC Arduino power source to energize the system. Here, for demonstration, three different color LEDs (Red, Green ...

It is a combination of 8 LEDs (the decimal point -DP- is the 8th), which can be arranged so that different combinations can be used to make numerical digits. Just follow the schematic circuit diagram ...

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 ...