Properly photographing a 3.5" floppy disk for archival is annoyingly complicated. The label has THREE sides!

I've already built an automated system to take a picture of the front of a disk, but really I need to take THREE photos if I want to get the whole thing.

That means either three cameras or I need to rotate the disk 90° and then 180°, which is going to really stress the limits of my mechanical engineering skills.

So the front is easy. The disk slides down a slide, it's stopped by a servo, I take a picture with a camera aimed down at it.

The back... Either I flip the disk, or I have a camera under the disk which takes a picture aimed up.

And the edge is the worst. I can't have a camera aimed at it unless I either move the camera out of the way of the disk, or I make the disk move in an L shape

How about this: I stick with the "stop disk and aim down" method, but I do it on a transparent surface, and I add some mirrors.

Then the disk can be photographed from three sides at once.

The only downside then is that the focus can't be exactly right, since the back/edge will be further away. I'd need to either adjust the focus while taking pictures or have some of the sides slightly out of focus

And the question of where to place the mirrors gets tricky. I'm not 100% I can even place them appropriately without getting really complicated with multiple mirrors, or having the mirrors be in the path of the disk

Mirrors could also cause a slowdown: if I can't mount them well enough that the motion of the disk and drive mechanism doesn't shake them, I've got to add an additional delay while I wait on the mirrors to stop vibrating so I can get a clean picture

If I can rotate the disk sideways I might be able to solve the edge problem. Then I could just have a second camera that aims at the edge.

I could rotate it sideways with some static obstacles, but I may need a servo mechanism or something to do a 180 flip to get the back, unless I do the transparent glass thing.

The disk comes out, it whacks into a bumper and rotates 90° sideways, and three separate cameras photograph it at once, then something ejects it?

The problem is that all possible answers for this problem (other than "don't worry about the edge and back") are either going to be tricky to design and fiddly to operate, and expensive in terms of cameras.

And some solutions are both.

The best designed option would probably be a sort of carrier that rotates. It'd have to grab the disk by the edges, but if it could move the disk from the original orientation, to 90° for the edge pic, then 180° for the back pic, it could then rotate to like 270° to drop the disk.

That might be the most reasonable option.
It would require variable focus on the camera, since the surface it's photographing is closer for the edge picture.

Or just a second camera mounted roughly parallel that is on fixed focus for the edge picture. That might be easier/cheaper to do, actually.

(since multiple fixed focus cameras for raspis can be cheaper than one camera with a motorized focus)