Can a bone rotation controlled with another bone?


I have an armature with some bones.
Is it possible to control a bone rotation with another bone.

I have tried using the transformation constrain, but then my target bone “jumps” back at some point.
The problem is the same a asked here :
modeling - Object Constraint - Object won’t make a 360º rotation - Blender Stack Exchange

So are there other ways of doing this?

You can use drivers

Animation Nodes is a good choice as well. There was also rigging nodes add-on that someone was working on.

Ok, I am using animation nodes now.

When I leave the “convert” and “math” node out it works fine.
But then my bones rotate at the same speed and I need them to rotate at a different speed.

When I add those in I get an error ( “conversion failed” and “value has a wrong type” )
What do I need to change to get it to work?

You are converting Euler to float than passing that back as Euler values. You need to use Euler math to do it properly.

Now I use this, which works nice!

But now I need - for two other bones - to go form rotation to location.
So after the math node I need another convert node, right?
What node do I need to use there?