Quote Originally Posted by edgas10 View Post
ok lets say that i use the mg996 servos, they can handle 11kg so its good enough for me.
the arm of the robot will have 20 cm in the first and 20 on second section (starting from base)
How do you know that is good enough for you?
Have you actually worked it out?
How much does everything weigh?

The 11kg is 11kg-cm - That means when supplied with 6V it can move an absolute maximum weight of 11kg that is attached to a point 1cm from the centre. You are proposing to stick a microphone, a microphone holder, a load of aluminium, connectors and several servos at a distance of 40cm, I seriously doubt an 11kg-cm servo will handle that load...

If you examine the previous link I sent you as an example, a different sized servo is used for every joint, because each joint in the chain needs to be stronger than the last to move the additional weight. You can't just throw together a random bunch stuff and hope it all works, that is fine if you are learning how to do things but will just end in failure and disappointment if you are trying to deliver an actual useful product.

PS I'm getting a bit confused as you keep drip feeding in various bits of information.

Are you trying to make a 'robot arm' like this:
Home Made Robot arm picks up coin - YouTube
Home Made Robot arm picks up coin - YouTube

Or do you actually want a 'motorised microphone' like these:
Mic robot prototype - YouTube
Richard Z. Kruspe on the Rammfire amp emulation - YouTube
Robot Mic Stand - YouTube