Thanks Matthew, it would be good to see a few more people give the continuous motion scanners a go. It just needs a brighter light at global shutter.
The bolt is an 8mm diameter one I had lying around. It’s worked well for the feed side to create a bit of a friction/slip clutch. There’s a lock nut on the front of it and a nylon washer, so the spring being compressed is pushing the washers against the 3D printed face to create some friction. The tighter I squash it, the more is applied.
I ground a flat spot on the bolt to allow locking the reel onto it to prevent free spinning.
I don’t have any tension control yet, it’s really just what I set with the spring, but tension would change as the reel fills/empties.
In the next build I’ll try add another motor on the supply, along with a dancer arm for some tension and a PID loop to control the feed and take up speeds. Not sure how well it will work!