Wiring the Arduino Opta DC motor controller system. Wiring the DC motor controller system is quite easy to do. With the project BOM components available, use the electronic circuit schematic diagram ...

So long as the 0V rail is connected to the Arduino 0V rail, the positive rail can be any dc voltage – more or less that the Arduino, so great for 12V motors. And it is compatible with both 5V and 3V ...