Robot arm control electronics

[D.C.]

but the person who wants the motorised mic needs 5 axis , so i think i´ts easy to make a robot arm.

Try reading this:

How to Build a Robot Tutorial - Society of Robots

Pay special attention to the very first sentence -

"About this Robot Arm Tutorial
The robot arm is probably the most mathematically complex robot you could ever build."

If someone has asked you to build a motorised mic and they are intending to pay you for that, why not build a motorised mic? If all you need is a motorised mic that moves around in front of a speaker you can do this by pulling apart a few old printers and reusing the bits. If you really, really want to use a robot arm why not buy one and use that?

Trying to design a 5dof from scratch that will be good enough for use in a very highly demanding production environment on your first attempt seems a little..... ambitious.