I am working on a project, and an aspect has come up where I would like to measure (track continuously) the X and Y position of an object across a 2D plane. The object is moved by a person, with the object's movement constrained to the 2D plane (so no Z-axis displacement).
- I would like measured position resolution of 1 mm, ideally 0.5 mm or better.
- The space over which the object moves is 30 cm X 30 cm.
- Whatever method of measurement I use shouldn't significantly constrict the movement of the object.
- Also, please just assume that the plane on which the object moves is air, and NOT an actual solid surface (for project-specific reasons that are hard to verbalize).
- The good news is: The object is completely OK to be modified as necessary (LED on top, or string attachments, or anything else).
What might be a method to get that kind of resolution?
I am considering various approaches, but I don't know if any of them will fulfill the resolution requirement. Since there aren't many constraints on my existing system, I am OK with even a complex / bulky implementation, just as long as it's precise enough.
Here are a couple of my ideas so far:
(1) Infrared-based range sensors (only need two actually)
(2) Two long calipers/micrometers connected from the object to the sides
(3) Two strings, each connected from the object to a freely bending strain gage leaf on the side