Position around pivot point

I’ve been searching for around an hour for an answer to this question (or guidance). Couldn’t get much help as it’s quite specific. Would greatly appreciate any wisdom.

I’m attempting to track the movement of an object as in my diagram.

A - Ball socket
B - Handle manipulating the position of the arrow

I’d like to be able to accurate calculate the movement distance of the point B / arrow head.

I assume I can do this by replacing the ball and socket joint with two rotary sensors. One mounted on the other, perpendicular to each other. However, I don’t really have the manufacturing skill to produce this - so I’m hoping someone can suggest a solution that doesn’t require me to weld something (which I have never done before!).

Many thanks!

PIVOT-QUESTION.png

Could you press a gear onto shaft?
Your going to need some way of knowing start position then either count gear teeth or have a missing tooth for ' 0 ' then gaps will be ' 1 ' (or vice versa) count to number of teeth or spaces then start over +1
You could probably find multiple gears in old VCR or similar (printers, old mechanical clock, etc)

2 hall effect sensors offset at 90 degrees

You don't say how much freedom you've got to design this, but I'd try to put a hinge on top to deal with the see-saw motion and a sleeve that is free to rotate around the shaft to deal with the rotation. That gives you two simple joints that need angular sensors fitting but neither of them seem particular complicated to fit.