Is there a mechanical auto focus add on for this little laser?

Lasers
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1

Is there a mechanical auto focus add on for this little laser? I am thinking of some sort of plunger that touches the material surface that would somehow either signal(LED) the correct focal length or if the Z was somehow automated just stop when it reached the correct focal length. I tried searching the group but found nothing.

2

I am working in a little device to use a visible laser to adjust the mirrors…

3

originally, the K40 has no Z setting and come with fix focal.
the lens focal is 50.8 mmm, the distance could be adjusted by raising the material manually with the help of a piece of wood mesuring about 50.5 mm (the difference is the material thickness).