I am currently working on a project involving multiple servos (6 or 7) and wanted to power them with my converted computer power supply (5V 22A). I am using an arduino uno and would like to power that with a 9V wall wart. I assume that i can do this as long as the ground between the Arduino and computer power supply are connected? Also, should I add components to protect the Arduino and if so, what?

Thanks,

 

Yes, just connect the grounds and the Arduino runs off the wart and the servos off the PC supply. All is klare, der comisar.

As far as protection goes... you have a 22 amp source there! Use a series fast action fuse and pray!