Seeking solution for alternative shape keys deformation

In this case, I would like the viewer to (hopefully using the logic nodes) to every time a click happens, the arm will move, to determine angle of incline. It is a goniometer. So i though about using the shape keys, in a way that on every click the viewer would advance one degree, all the way to 90, depending on the situation.
With shape keys the arm deforms…big time. Then I tried adding a lot of vertical loops to the arm but still happens.
What kind of solution can I have for this one?? If I use armature?

Thank you again for so much help I get !! I am attaching the file. Also, as a second question: If i want to plainly use the material for color, could you please check if when I export it will show? it is just one color anyway…


Again, a billion thanks for everyone here!!!!!

Currently there is no apility of armature controlling with nodes. You can rotate a separate object. See attachment. I used transformation in local space so if you will click too many times on the buttons, the arrow can have an offset due to accumulated calculation errors. To avoid this you can use world space, but you will have to modify the logic a bit. But I think you will not notice the errors. See attached file.