The Arduino Opta has three versions of PLCs. The three versions consist of the Lite, the RS485, and connectivity units. The connectivity units are Bluetooth, Wi-Fi, and Ethernet. The connectivity ...

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 ...