Why don't Arduinos run on 5V

Sure, if you need more voltage, than you should input more voltage :slight_smile:
I am not powering anything above 5V and 5V-MicroUSB becomes widely available, so I think that is the way to go for me. Before I am having the PCB made I will test a bit on the breadboard, complete the software and then I will present the project and ask for specific comments :slight_smile: